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Brinkley DM, Smith KC, Fink EC, Kwen W, Yoo NH, West Z, Sullivan NL, Farthing AS, Hale VA, Goutte C. Notch signaling without the APH-2/nicastrin subunit of gamma secretase in Caenorhabditis elegans germline stem cells. Genetics 2024; 227:iyae076. [PMID: 38717968 DOI: 10.1093/genetics/iyae076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 05/01/2024] [Indexed: 07/09/2024] Open
Abstract
The final step in Notch signaling activation is the transmembrane cleavage of Notch receptor by γ secretase. Thus far, genetic and biochemical evidence indicates that four subunits are essential for γ secretase activity in vivo: presenilin (the catalytic core), APH-1, PEN-2, and APH-2/nicastrin. Although some γ secretase activity has been detected in APH-2/nicastrin-deficient mammalian cell lines, the lack of biological relevance for this activity has left the quaternary γ secretase model unchallenged. Here, we provide the first example of in vivo Notch signal transduction without APH-2/nicastrin. The surprising dispensability of APH-2/nicastrin is observed in Caenorhabditis elegans germline stem cells (GSCs) and contrasts with its essential role in previously described C. elegans Notch signaling events. Depletion of GLP-1/Notch, presenilin, APH-1, or PEN-2 causes a striking loss of GSCs. In contrast, aph-2/nicastrin mutants maintain GSCs and exhibit robust and localized expression of the downstream Notch target sygl-1. Interestingly, APH-2/nicastrin is normally expressed in GSCs and becomes essential under conditions of compromised Notch function. Further insight is provided by reconstituting the C. elegans γ secretase complex in yeast, where we find that APH-2/nicastrin increases but is not essential for γ secretase activity. Together, our results are most consistent with a revised model of γ secretase in which the APH-2/nicastrin subunit has a modulatory, rather than obligatory role. We propose that a trimeric presenilin-APH-1-PEN-2 γ secretase complex can provide a low level of γ secretase activity, and that cellular context determines whether or not APH-2/nicastrin is essential for effective Notch signal transduction.
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Affiliation(s)
- David M Brinkley
- Program in Biochemistry and Biophysics, Amherst College, Amherst, MA 01002, USA
| | - Karen C Smith
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Emma C Fink
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Woohyun Kwen
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Nina H Yoo
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Zachary West
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Nora L Sullivan
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Alex S Farthing
- Program in Biochemistry and Biophysics, Amherst College, Amherst, MA 01002, USA
| | - Valerie A Hale
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Caroline Goutte
- Program in Biochemistry and Biophysics, Amherst College, Amherst, MA 01002, USA
- Department of Biology, Amherst College, Amherst, MA 01002, USA
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Nayak V, Patra S, Rout S, Jena AB, Sharma R, Pattanaik KP, Singh J, Pandey SS, Singh RP, Majhi S, Singh KR, Kerry RG. Regulation of neuroinflammation in Alzheimer's disease via nanoparticle-loaded phytocompounds with anti-inflammatory and autophagy-inducing properties. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 122:155150. [PMID: 37944239 DOI: 10.1016/j.phymed.2023.155150] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 09/23/2023] [Accepted: 10/14/2023] [Indexed: 11/12/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is characterized by neuroinflammation linked to amyloid β (Aβ) aggregation and phosphorylated tau (τ) protein in neurofibrillary tangles (NFTs). Key elements in Aβ production and NFT assembly, like γ-secretase and p38 mitogen-activated protein kinase (p38MAPK), contribute to neuroinflammation. In addition, impaired proteosomal and autophagic pathways increase Aβ and τ aggregation, leading to neuronal damage. Conventional neuroinflammation drugs have limitations due to unidirectional therapeutic approaches and challenges in crossing the Blood-Brain Barrier (BBB). Clinical trials for non-steroidal anti-inflammatory drugs (NSAIDs) and other therapeutics remain uncertain. Novel strategies addressing the complex pathogenesis and BBB translocation are needed to effectively tackle AD-related neuroinflammation. PURPOSE The current scenario demands for a much-sophisticated theranostic measures which could be achieved via customized engineering and designing of novel nanotherapeutics. As, these therapeutics functions as a double edge sword, having the efficiency of unambiguous targeting, multiple drug delivery and ability to cross BBB proficiently. METHODS Inclusion criteria involve selecting recent, English-language studies from the past decade (2013-2023) that explore the regulation of neuroinflammation in neuroinflammation, Alzheimer's disease, amyloid β, tau protein, nanoparticles, autophagy, and phytocompounds. Various study types, including clinical trials, experiments, and reviews, were considered. Exclusion criteria comprised non-relevant publication types, studies unrelated to Alzheimer's disease or phytocompounds, those with methodological flaws, duplicates, and studies with inaccessible data. RESULTS In this study, polymeric nanoparticles loaded with specific phytocompounds and coated with an antibody targeting the transferrin receptor (anti-TfR) present on BBB. Thereafter, the engineered nanoparticles with the ability to efficiently traverse the BBB and interact with target molecules within the brain, could induce autophagy, a cellular process crucial for neuronal health, and exhibit potent anti-inflammatory effects. Henceforth, the proposed combination of desired phytocompounds, polymeric nanoparticles, and anti-TfR coating presents a promising approach for targeted drug delivery to the brain, with potential implications in neuroinflammatory conditions such as Alzheimer's disease.
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Affiliation(s)
- Vinayak Nayak
- ICAR- National Institute on Foot and Mouth Disease-International Centre for Foot and Mouth Disease, Arugul, Bhubaneswar, Odisha (752050), India
| | - Sushmita Patra
- Advanced Centre for Treatment, Research and Education in Cancer, Tata Memorial Centre, Kharghar, Navi Mumbai, Maharashtra (410210), India
| | - Shrushti Rout
- Department of Biotechnology, Utkal University, Vani Vihar, Bhubaneswar, Odisha (751004), India
| | - Atala Bihari Jena
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA (02115), United States of America
| | - Rohit Sharma
- Department of Rasa Shastra and Bhaishajya Kalpana, Faculty of Ayurveda, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh (221005), India
| | - Kali Prasad Pattanaik
- School of Biotechnology, Kalinga Institute of Industrial Technology (KIIT), Deemed to be University, Bhubaneswar 751024, India
| | - Jay Singh
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh (221005), India
| | - Shyam S Pandey
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu (8080196), Japan
| | - Ravindra Pratap Singh
- Department of Biotechnology, Faculty of Science, Indira Gandhi National Tribal University, Amarkantak, Madhya Pradesh 484887, India
| | - Sanatan Majhi
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA (02115), United States of America
| | - Kshitij Rb Singh
- Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu (8080196), Japan.
| | - Rout George Kerry
- Department of Biotechnology, Utkal University, Vani Vihar, Bhubaneswar, Odisha (751004), India.
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Comparative proteomic profiles of Schistosoma japonicum male worms derived from single-sex and bisexual infections. Int J Parasitol 2022; 52:815-828. [PMID: 36265673 DOI: 10.1016/j.ijpara.2022.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 08/29/2022] [Accepted: 09/01/2022] [Indexed: 11/05/2022]
Abstract
Schistosomiasis, which is caused by parasitic schistosomes, remains the second most prevalent parasitic disease of mammals worldwide. To successfully maintain fecundity, schistosomes have evolved a lifecycle that involves the cooperation of morphologically distinct male and female forms. Eggs produced by worm pairs are vital to the lifecycle of the parasite and are responsible for pathogenesis. Understanding the reproductive mechanism of schistosomes will help to control infection. In this study, the proteomic profiles of single-sex infected male (SM) worms and bisexual infected mated male (MM) worms of Schistosoma japonicum at 18, 21, 23, and 25 days p.i. were identified through data-independent acquisition. In total, 674 differentially expressed proteins (DEPs) were identified for the SM and MM worms at all four timepoints. Bioinformatic analysis demonstrated that most of the DEPs were involved in biosynthetic processes including locomotion, cell growth and death, cell motility, and metabolic processes such as protein metabolism and glucose metabolism. Schistosoma japonicum glycosyltransferase (SjGT) and S. japonicum nicastrin protein (SjNCSTN) were selected for quantitative real‑time PCR analysis and long-term interference with small interfering RNA (siRNA) to further explore the functions of the DEPs. Sjgt mRNA expression was mainly enriched in male worms, while Sjncstn was enriched in both sexes. siRNA against SjGT and SjNCSTN resulted in minor morphological changes in the testes of male worms and significant decreased vitality and fertility. The present study provides comprehensive proteomic profiles of S. japonicum SM and MM worms at 18, 21, 23, and 25 days p.i. and offers insights into the mechanisms underlying the growth and maturation of schistosomes.
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Sugawara K, Ogawa W. New mechanism of metformin action mediated by lysosomal presenilin enhancer 2. J Diabetes Investig 2022; 14:12-14. [PMID: 36308027 PMCID: PMC9807141 DOI: 10.1111/jdi.13925] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 01/07/2023] Open
Abstract
Formation of the PEN2-ATP6AP1 complex induced by the binding of metformin to PEN2 results in the inhibition of v-ATPase activity and in the recruitment of AXIN/LKB1 to lysosomes, which in turn results in the phosphorylation and activation of AMPK.
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Affiliation(s)
- Kenji Sugawara
- Division of Diabetes and Endocrinology, Department of Internal MedicineKobe University Graduate School of MedicineKobeJapan
| | - Wataru Ogawa
- Division of Diabetes and Endocrinology, Department of Internal MedicineKobe University Graduate School of MedicineKobeJapan
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Hidradenitis Suppurativa: A Perspective on Genetic Factors Involved in the Disease. Biomedicines 2022; 10:biomedicines10082039. [PMID: 36009585 PMCID: PMC9406067 DOI: 10.3390/biomedicines10082039] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/22/2022] Open
Abstract
Hidradenitis Suppurativa (HS) is a chronic inflammatory skin disease of the pilosebaceous unit, clinically consisting of painful nodules, abscesses, and sinus tracts mostly in, but not limited to, intertriginous skin areas. HS can be defined as a complex skin disease with multifactorial etiologies, including—among others—genetic, immunologic, epigenetic, and environmental factors. Based on genetic heterogeneity and complexity, three different forms can be recognized and considered separately as sporadic, familial, and syndromic. To date, several genetic variants associated to disease susceptibility, disease-onset, and/or treatment response have been reported; some of these reside in genes encoding the gamma-secretase subunits whereas others involve autoinflammatory and/or keratinization genes. The aim of this perspective work is to provide an overview of the contribution of several genetic studies encompassing family linkage analyses, target candidate gene studies, and -omic studies in this field. In our viewpoint, we discuss the role of genetics in Hidradenitis suppurativa considering findings based on Sanger sequencing as well as the more recent Next Generation Sequencing (i.e., exome sequencing or RNA Sequencing) with the aim of better understanding the etio-pathogenesis of the disease as well as identifying novel therapeutic strategies.
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Garcovich S, Tricarico PM, Meddour CN, Giovanardi G, Peris K, Crovella S, Boniotto M. Comorbid acne inversa and Dowling-Degos disease due to a single NCSTN mutation: is there enough evidence? Reply from the authors. Br J Dermatol 2021; 184:375-376. [PMID: 32895925 DOI: 10.1111/bjd.19543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- S Garcovich
- Dermatology, Department of Medical and Surgical Sciences, Fondazione Policlinico A. Gemelli IRCCS, Rome, Italy
- Università Cattolica del Sacro Cuore, Rome, Italy
| | - P M Tricarico
- Department of Advanced Diagnostics, Institute for Maternal and Child Health-IRCCS 'Burlo Garofolo', Trieste, Italy
| | - C N Meddour
- University of Paris Est-Créteil, Créteil, France
- Institut Mondor for Biomedical Research/INSERM U955 Team 16, Créteil, France
| | - G Giovanardi
- Dermatology, Department of Medical and Surgical Sciences, Fondazione Policlinico A. Gemelli IRCCS, Rome, Italy
- Università Cattolica del Sacro Cuore, Rome, Italy
| | - K Peris
- Dermatology, Department of Medical and Surgical Sciences, Fondazione Policlinico A. Gemelli IRCCS, Rome, Italy
- Università Cattolica del Sacro Cuore, Rome, Italy
| | - S Crovella
- Department of Advanced Diagnostics, Institute for Maternal and Child Health-IRCCS 'Burlo Garofolo', Trieste, Italy
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - M Boniotto
- University of Paris Est-Créteil, Créteil, France
- Institut Mondor for Biomedical Research/INSERM U955 Team 16, Créteil, France
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7
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Li H, Lan T, Xu L, Liu H, Wang J, Li J, Chen X, Huang J, Li X, Yuan K, Zeng Y, Wu H. NCSTN promotes hepatocellular carcinoma cell growth and metastasis via β-catenin activation in a Notch1/AKT dependent manner. J Exp Clin Cancer Res 2020; 39:128. [PMID: 32631394 PMCID: PMC7339515 DOI: 10.1186/s13046-020-01638-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 07/01/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Hepatocellular carcinoma is the third top cause of cancer-related mortalities worldwide. The prognosis of HCC patients remains poor due to rapid progression and high incidence of tumor recurrence. Nicastrin (NCSTN), a core subunit of γ-Secretase, has been reported to play a vital role in tumor progression. However, no study till now has revealed its role in HCC. METHODS The expression of NCSTN was evaluated by immunohistochemical staining, Western blot, and quantitative real-time PCR. Cell counting kit-8, colony formation and cell cycle assays were used for evaluating cell growth in vitro. Transwell and wound-healing assays were used for evaluating cell migration and invasion capacity. Immunofluorescence, subcellular protein fractionation and co-immunoprecipitation were used for location analysis of β-catenin. The in vivo functions of NCSTN were illustrated by xenograft tumor models. RESULTS NCSTN was dramatically overexpressed in HCC compared to normal liver tissues. Elevated NCSTN expression level was significantly correlated to worse overall and recurrence-free survival of HCC patients. Enhanced NCSTN expression promoted HCC cell growth, migration and invasion in vitro and in vivo. Mechanistic investigations showed that NCSTN induced epithelial-mesenchymal transition (EMT) process via upregulation of Zeb1. Subsequently, we revealed that NCSTN facilitated nuclear translocation of β-catenin, a positive transcriptional regulator of Zeb1. Using Notch and AKT inhibitors, we revealed that NCSTN promoted β-catenin activation through Notch1 and AKT signaling pathway. NCSTN increased AKT and GSK-3β phosphorylation by cleavage of Notch1, which decreased GSK-3β/β-catenin complex. The inactivation of GSK-3β inhibited the β-catenin degradation and promoted nuclear translocation of β-catenin to initiate transcription of Zeb1, resulting in malignant phenotype. CONCLUSIONS Our results demonstrated that NCSTN promoted HCC cell growth and metastasis via β-catenin-mediated upregulation of Zeb1 in a Notch1/AKT dependent manner, suggesting that NCSTN might serve as a potential prognostic marker and therapeutic target for HCC.
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Affiliation(s)
- Hui Li
- grid.13291.380000 0001 0807 1581Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China ,grid.13291.380000 0001 0807 1581Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Tian Lan
- grid.13291.380000 0001 0807 1581Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China ,grid.13291.380000 0001 0807 1581Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Lin Xu
- grid.13291.380000 0001 0807 1581Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Hailing Liu
- grid.13291.380000 0001 0807 1581Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China ,grid.13291.380000 0001 0807 1581Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Jinju Wang
- grid.13291.380000 0001 0807 1581Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China ,grid.13291.380000 0001 0807 1581Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Jiaxin Li
- grid.13291.380000 0001 0807 1581Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China ,grid.13291.380000 0001 0807 1581Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Xiangzheng Chen
- grid.13291.380000 0001 0807 1581Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China ,grid.13291.380000 0001 0807 1581Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Jiwei Huang
- grid.13291.380000 0001 0807 1581Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China ,grid.13291.380000 0001 0807 1581Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041 China
| | - Xuefeng Li
- grid.410737.60000 0000 8653 1072School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, 511436 China ,grid.263488.30000 0001 0472 9649Shenzhen Luohu People’s Hospital, The Third Affiliated Hospital of Shenzhen University, Shenzhen, 518001 China
| | - Kefei Yuan
- Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041, China. .,Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Yong Zeng
- Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041, China. .,Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Hong Wu
- Department of Liver Surgery, Liver Transplantation Division, Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041, China. .,Laboratory of Liver Surgery, West China Hospital, Sichuan University, Chengdu, 610041, China.
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Kabir MT, Uddin MS, Setu JR, Ashraf GM, Bin-Jumah MN, Abdel-Daim MM. Exploring the Role of PSEN Mutations in the Pathogenesis of Alzheimer's Disease. Neurotox Res 2020; 38:833-849. [PMID: 32556937 DOI: 10.1007/s12640-020-00232-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/24/2020] [Accepted: 05/28/2020] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia. Mutations of presenilin (PSEN) genes that encode presenilin proteins have been found as the vital causal factors for early-onset familial AD (FAD). AD pathological features such as memory loss, synaptic dysfunction, and formation of plaques have been successfully mimicked in the transgenic mouse models that coexpress FAD-related presenilin and amyloid precursor protein (APP) variants. γ-Secretase (GS) is an enzyme that plays roles in catalyzing intramembranous APP proteolysis to release pathogenic amyloid beta (Aβ). It has been found that presenilins can play a role as the GS's catalytic subunit. FAD-related mutations in presenilins can modify the site of GS cleavage in a way that can elevate the production of longer and highly fibrillogenic Aβ. Presenilins can interact with β-catenin to generate presenilin complexes. Aforesaid interactions have also been studied to observe the mutational and physiological activities in the catenin signal transduction pathway. Along with APP, GS can catalyze intramembrane proteolysis of various substrates that play a vital role in synaptic function. PSEN mutations can cause FAD with autosomal dominant inheritance and early onset of the disease. In this article, we have reviewed the current progress in the analysis of PSENs and the correlation of PSEN mutations and AD pathogenesis.
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Affiliation(s)
| | - Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh. .,Pharmakon Neuroscience Research Network, Dhaka, Bangladesh.
| | | | - Ghulam Md Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - May N Bin-Jumah
- Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, 11474, Saudi Arabia
| | - Mohamed M Abdel-Daim
- Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh, 11451, Saudi Arabia.,Pharmacology Department, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, 41522, Egypt
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Gupta SP, Patil VM. Recent Studies on Design and Development of Drugs Against Alzheimer's Disease (AD) Based on Inhibition of BACE-1 and Other AD-causative Agents. Curr Top Med Chem 2020; 20:1195-1213. [PMID: 32297584 DOI: 10.2174/1568026620666200416091623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/13/2020] [Accepted: 01/15/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is one of the neurodegenerative diseases and has been hypothesized to be a protein misfolding disease. In the generation of AD, β-secretase, γ-secretase, and tau protein play an important role. A literature search reflects ever increasing interest in the design and development of anti-AD drugs targeting β-secretase, γ-secretase, and tau protein. OBJECTIVE The objective is to explore the structural aspects and role of β-secretase, γ-secretase, and tau protein in AD and the efforts made to exploit them for the design of effective anti-AD drugs. METHODS The manuscript covers the recent studies on design and development of anti-AD drugs exploiting amyloid and cholinergic hypotheses. RESULTS Based on amyloid and cholinergic hypotheses, effective anti-AD drugs have been searched out in which non-peptidic BACE1 inhibitors have been most prominent. CONCLUSION Further exploitation of the structural aspects and the inhibition mechanism for β-secretase, γ-secretase, and tau protein and the use of cholinergic hypothesis may lead still more potent anti-AD drugs.
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Affiliation(s)
- Satya P Gupta
- Department of Pharmaceutical Technology, Meerut Institute of Engineering and Technology, Meerut-250005, India
| | - Vaishali M Patil
- Computer Aided Drug Design Lab, Department of Pharmaceutical Chemistry, KIET School of Pharmacy, KIET Group of Institutions, Delhi-NCR, Ghaziabad-201206, Uttar Pradesh, India
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10
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Vossen ARJV, van Straalen KR, Swagemakers SMA, de Klein JEMM, Stubbs AP, Venter DJ, van der Zee HH, van der Spek PJ, Prens EP. A novel nicastrin mutation in a three-generation Dutch family with hidradenitis suppurativa: a search for functional significance. J Eur Acad Dermatol Venereol 2020; 34:2353-2361. [PMID: 32078194 PMCID: PMC7586943 DOI: 10.1111/jdv.16310] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/30/2020] [Indexed: 12/12/2022]
Abstract
Background Mutations in the γ‐secretase enzyme subunits have been described in multiple kindreds with familial hidradenitis suppurativa (HS). Objective In this study, we report a novel nicastrin (NCSTN) mutation causing HS in a Dutch family. We sought to explore the immunobiological function of NCSTN mutations using data of the Immunological Genome Project. Methods Blood samples of three affected and two unaffected family members were collected. Whole‐genome sequencing was performed using genomic DNA isolated from peripheral blood leucocytes. Sanger sequencing was done to confirm the causative NCSTN variant and the familial segregation. The microarray data set of the Immunological Genome Project was used for thorough dissection of the expression and function of wildtype NCSTN in the immune system. Results In a family consisting of 23 members, we found an autosomal dominant inheritance pattern of HS and detected a novel splice site mutation (c.1912_1915delCAGT) in the NCSTN gene resulting in a frameshift and subsequent premature stop. All affected individuals had HS lesions on non‐flexural and atypical locations. Wildtype NCSTN appears to be upregulated in myeloid cells like monocytes and macrophages, and in mesenchymal cells such as fibroblastic reticular cells and fibroblasts. In addition, within the 25 highest co‐expressed genes with NCSTN we identified CAPNS1,ARNT and PPARD. Conclusion This study reports the identification a novel NCSTN gene splice site mutation which causes familial HS. The associated immunobiological functions of NCSTN and its co‐expressed genes ARNT and PPARD link genetics to the most common environmental and metabolic HS risk factors which are smoking and obesity.
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Affiliation(s)
- A R J V Vossen
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - K R van Straalen
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - S M A Swagemakers
- Department of Pathology and Clinical Bioinformatics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - J E M M de Klein
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A P Stubbs
- Department of Pathology and Clinical Bioinformatics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - D J Venter
- Department of Pathology, Mater Health Services, South Brisbane, Queensland, Australia
| | - H H van der Zee
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - P J van der Spek
- Department of Pathology and Clinical Bioinformatics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - E P Prens
- Department of Dermatology, Erasmus University Medical Center, Rotterdam, The Netherlands
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11
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Lombardo S, Chiacchiaretta M, Tarr A, Kim W, Cao T, Sigal G, Rosahl TW, Xia W, Haydon PG, Kennedy ME, Tesco G. BACE1 partial deletion induces synaptic plasticity deficit in adult mice. Sci Rep 2019; 9:19877. [PMID: 31882662 PMCID: PMC6934620 DOI: 10.1038/s41598-019-56329-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 12/10/2019] [Indexed: 12/13/2022] Open
Abstract
BACE1 is the first enzyme involved in APP processing, thus it is a strong therapeutic target candidate for Alzheimer's disease. The observation of deleterious phenotypes in BACE1 Knock-out (KO) mouse models (germline and conditional) raised some concerns on the safety and tolerability of BACE1 inhibition. Here, we have employed a tamoxifen inducible BACE1 conditional Knock-out (cKO) mouse model to achieve a controlled partial depletion of BACE1 in adult mice. Biochemical and behavioural characterization was performed at two time points: 4-5 months (young mice) and 12-13 months (aged mice). A ~50% to ~70% BACE1 protein reduction in hippocampus and cortex, respectively, induced a significant reduction of BACE1 substrates processing and decrease of Aβx-40 levels at both ages. Hippocampal axonal guidance and peripheral nerve myelination were not affected. Aged mice displayed a CA1 long-term potentiation (LTP) deficit that was not associated with memory impairment. Our findings indicate that numerous phenotypes observed in germline BACE1 KO reflect a fundamental role of BACE1 during development while other phenotypes, observed in adult cKO, may be absent when partially rather than completely deleting BACE1. However, we demonstrated that partial depletion of BACE1 still induces CA1 LTP impairment, supporting a role of BACE1 in synaptic plasticity in adulthood.
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Affiliation(s)
- Sylvia Lombardo
- Alzheimer's Disease Research Laboratory, Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
| | - Martina Chiacchiaretta
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
| | - Andrew Tarr
- Circuits and Behaviour Core, Center for Neuroscience Research, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
| | - WonHee Kim
- Alzheimer's Disease Research Laboratory, Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
| | - Tingyi Cao
- Alzheimer's Disease Research Laboratory, Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
| | - Griffin Sigal
- Alzheimer's Disease Research Laboratory, Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
| | - Thomas W Rosahl
- External In Vivo Pharmacology, Merck & Co. Inc., Kenilworth, NJ, 07033, USA
| | - Weiming Xia
- Geriatric Research, Education and Clinic Center, Bedford Veterans Affairs Medical Center, Bedford, MA, 01730, USA
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, 02118, USA
| | - Philip G Haydon
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA
| | | | - Giuseppina Tesco
- Alzheimer's Disease Research Laboratory, Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA.
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts, 02111, USA.
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12
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Ceylan H, Budak H, Kocpinar EF, Baltaci NG, Erdogan O. Examining the link between dose-dependent dietary iron intake and Alzheimer's disease through oxidative stress in the rat cortex. J Trace Elem Med Biol 2019; 56:198-206. [PMID: 31525623 DOI: 10.1016/j.jtemb.2019.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/01/2019] [Accepted: 09/08/2019] [Indexed: 12/17/2022]
Abstract
BACKGROUND Neurodegenerative diseases such as Alzheimer's and Parkinson's disease are characterized by the progressive deterioration of the structure and function of the nervous system. A number of environmental risk factors including potentially toxic elements such as iron, lead to negative effects on many metabolic reactions as well as neuroprotection. The aim of this study is to reveal whether long-term iron overload is one of the underlying factors in the pathogenesis of Alzheimer's disease (AD). METHODS 15 young-adult male rats were randomly divided into 5 groups treated with iron through drinking water for 4 months. Following feeding, the iron content, reduced glutathione (GSH), and hydrogen peroxide (H2O2) levels of cortex tissues were measured. Specific enzyme activities were determined spectrophotometrically. mRNA expression profiles were measured using real-time PCR (qPCR). RESULTS Iron levels were elevated in case of non-toxic (0.87 and 3 μg/mL) iron administration. However, no changes were observed in toxic (30 and 300 μg/mL) iron administration. GSH and H2O2 levels altered with long-term iron overload. Glutathione peroxidase (GPx) enzyme activities significantly increased in all groups, while glutathione S-transferase (GST) activity increased only in case of 0.87 and 30 μg/mL iron administration. Expression levels of neuroprotective and AD-related genes were altered by 3 μg/mL iron overload in a dose-dependent manner. The expression and activity of acetylcholinesterase (AChE) were elevated at 3 μg/mL iron concentration. CONCLUSION The findings of the present study allow us to conclude that long-term dietary iron intake, especially at a dose of 3 μg/mL demonstrates negative effects on the rat cortex by provoking antioxidant metabolism and AD pathology in a dose-dependently.
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Affiliation(s)
- Hamid Ceylan
- Science Faculty, Department of Molecular Biology and Genetics, Atatürk University, Erzurum, Turkey.
| | - Harun Budak
- Science Faculty, Department of Molecular Biology and Genetics, Atatürk University, Erzurum, Turkey
| | - Enver Fehim Kocpinar
- Science Faculty, Department of Molecular Biology and Genetics, Atatürk University, Erzurum, Turkey; Vocational School, Department of Medical Services and Techniques, Muş Alparslan University, Mus, Turkey
| | - Nurdan Gonul Baltaci
- Science Faculty, Department of Molecular Biology and Genetics, Atatürk University, Erzurum, Turkey
| | - Orhan Erdogan
- Science Faculty, Department of Molecular Biology and Genetics, Atatürk University, Erzurum, Turkey
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13
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Xie Y, Niu M, Ji C, Huang TY, Zhang C, Tian Y, Shi Z, Wang C, Zhao Y, Luo H, Can D, Xu H, Zhang YW, Zhang X. SNX8 Enhances Non-amyloidogenic APP Trafficking and Attenuates Aβ Accumulation and Memory Deficits in an AD Mouse. Front Cell Neurosci 2019; 13:410. [PMID: 31551717 PMCID: PMC6743354 DOI: 10.3389/fncel.2019.00410] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 08/26/2019] [Indexed: 12/13/2022] Open
Abstract
Dysregulation of various APP trafficking components in the endosome has been previously implicated in Alzheimer’s disease (AD). Although single nucleotide polymorphisms within the gene locus encoding the endosomal component, SNX8 have been previously associated with AD, how SNX8 levels are altered and its contribution to AD onset is currently unknown. Here, we observe decreased expression of SNX8 in human AD and AD mouse brain. SNX8 predominantly localized to early and late endosomes, where SNX8 overexpression enhanced total APP levels, cell surface APP distribution and consequent soluble APPα cleavage. SNX8 depletion resulted in elevated β-amyloid (Aβ) levels, while SNX8 overexpression reduced Aβ levels in cells and in an APP/PS1 AD mouse model. Importantly, SNX8 overexpression rescued cognitive impairment in APP/PS1 mice. Together, these results implicate a neuroprotective role for SNX8 in enhancing non-amyloidogenic APP trafficking and processing pathways. Given that endosomal dysfunction is an early event in AD, restoration of dysfunctional endosomal components such as SNX8 may be beneficial in future therapeutic strategies.
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Affiliation(s)
- Yongzhuang Xie
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Mengxi Niu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Chengxiang Ji
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Timothy Y Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Cuilin Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China.,The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou, China
| | - Ye Tian
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Zhun Shi
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Chen Wang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China.,Department of Neurology, The First Affiliated Hospital, School of Medicine, Xiamen University, Xiamen, China
| | - Yingjun Zhao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Hong Luo
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Dan Can
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
| | - Xian Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, School of Medicine, Xiamen University, Xiamen, China
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14
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Hsu CH, Liou GG, Jiang YJ. Nicastrin Deficiency Induces Tyrosinase-Dependent Depigmentation and Skin Inflammation. J Invest Dermatol 2019; 140:404-414.e13. [PMID: 31437444 DOI: 10.1016/j.jid.2019.07.702] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 12/19/2022]
Abstract
Skin depigmentation diseases, such as vitiligo, are pigmentation disorders that often destroy melanocytes. However, their pathological mechanisms remain unclear, and therefore, promising treatments or prevention has been lacking. Here, we demonstrate that a zebrafish insertional mutant showing a significant reduction of nicastrin transcript possesses melanosome maturation defect, Tyrosinase-dependent mitochondrial swelling, and melanophore cell death. The depigmentation phenotypes are proven to be a result of γ-secretase inactivation. Furthermore, live imaging demonstrates that macrophages are recruited to and can phagocytose melanophore debris. Thus, we characterize a potential zebrafish depigmentation disease model, a nicastrinhi1384 mutant, which can be used for further treatment or drug development of diseases related to skin depigmentation and/or inflammation.
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Affiliation(s)
- Chia-Hao Hsu
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan; Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Gunn-Guang Liou
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yun-Jin Jiang
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan; Biotechnology Center, National Chung Hsing University, Taichung, Taiwan; Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan; Department of Life Science, Tunghai University, Taichung, Taiwan.
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15
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Petit D, Hitzenberger M, Lismont S, Zoltowska KM, Ryan NS, Mercken M, Bischoff F, Zacharias M, Chávez-Gutiérrez L. Extracellular interface between APP and Nicastrin regulates Aβ length and response to γ-secretase modulators. EMBO J 2019; 38:e101494. [PMID: 31109937 PMCID: PMC6576158 DOI: 10.15252/embj.2019101494] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 04/02/2019] [Accepted: 04/11/2019] [Indexed: 12/20/2022] Open
Abstract
γ-Secretase complexes (GSECs) are multimeric membrane proteases involved in a variety of physiological processes and linked to Alzheimer's disease (AD). Presenilin (PSEN, catalytic subunit), Nicastrin (NCT), Presenilin Enhancer 2 (PEN-2), and Anterior Pharynx Defective 1 (APH1) are the essential subunits of GSECs. Mutations in PSEN and the Amyloid Precursor Protein (APP) cause early-onset AD GSECs successively cut APP to generate amyloid-β (Aβ) peptides of various lengths. AD-causing mutations destabilize GSEC-APP/Aβn interactions and thus enhance the production of longer Aβs, which elicit neurotoxic events underlying pathogenesis. Here, we investigated the molecular strategies that anchor GSEC and APP/Aβn during the sequential proteolysis. Our studies reveal that a direct interaction between NCT ectodomain and APPC99 influences the stability of GSEC-Aβn assemblies and thereby modulates Aβ length. The data suggest a potential link between single-nucleotide variants in NCSTN and AD risk. Furthermore, our work indicates that an extracellular interface between the protease (NCT, PSEN) and the substrate (APP) represents the target for compounds (GSMs) modulating Aβ length. Our findings may guide future rationale-based drug discovery efforts.
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Affiliation(s)
- Dieter Petit
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Manuel Hitzenberger
- Physics Department, Theoretical Biophysics (T38), Technical University of Munich, München, Germany
| | - Sam Lismont
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Katarzyna Marta Zoltowska
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
| | - Natalie S Ryan
- Dementia Research Centre, Department of Neurodegenerative Disease UCL Queen Square Institute of Neurology, London, UK
| | - Marc Mercken
- Janssen Research & Development, Division of Janssen Pharmaceutica NV, Beerse, Belgium
- Janssen Research & Development, Neuroscience biology Turnhoutseweg, Beerse, Belgium
| | - François Bischoff
- Janssen Research & Development, Division of Janssen Pharmaceutica NV, Beerse, Belgium
| | - Martin Zacharias
- Physics Department, Theoretical Biophysics (T38), Technical University of Munich, München, Germany
| | - Lucía Chávez-Gutiérrez
- VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), KU Leuven, Leuven, Belgium
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16
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Yuksel M, Tacal O. Trafficking and proteolytic processing of amyloid precursor protein and secretases in Alzheimer's disease development: An up-to-date review. Eur J Pharmacol 2019; 856:172415. [PMID: 31132354 DOI: 10.1016/j.ejphar.2019.172415] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/26/2019] [Accepted: 05/23/2019] [Indexed: 12/25/2022]
Abstract
Alzheimer's disease (AD), which is predicted to affect 1 in 85 persons worldwide by 2050, results in progressive loss of neuronal functions, leading to impairments in memory and cognitive abilities. As being one of the major neuropathological hallmarks of AD, senile plaques mainly consist of amyloid-β (Aβ) peptides, which are derived from amyloid precursor protein (APP) via the sequential cleavage by β- and γ-secretases. Although the overproduction and accumulation of Aβ peptides are at the center of AD research, the new discoveries point out to the complexity of the disease development. In this respect, it is crucial to understand the processing and the trafficking of APP, the enzymes involved in its processing, the cleavage products and their therapeutic potentials. This review summarizes the salient features of APP processing focusing on APP, the canonical secretases as well as the novel secretases and the cleavage products with an update of the recent developments. We also discussed the intracellular trafficking of APP and secretases in addition to their potential in AD therapy.
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Affiliation(s)
- Melike Yuksel
- Department of Biochemistry, School of Pharmacy, Hacettepe University, 06100, Ankara, Turkey.
| | - Ozden Tacal
- Department of Biochemistry, School of Pharmacy, Hacettepe University, 06100, Ankara, Turkey.
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17
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Hitzenberger M, Zacharias M. Structural Modeling of γ-Secretase Aβ n Complex Formation and Substrate Processing. ACS Chem Neurosci 2019; 10:1826-1840. [PMID: 30638370 DOI: 10.1021/acschemneuro.8b00725] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The intramembrane aspartyl protease γ-secretase (GSEC) cleaves single-span transmembrane helices including the C-terminal fragment of the amyloid precursor protein (APP). This substrate is initially cleaved at the ϵ-site followed by successive processing (trimming) events mostly in steps of three amino acids. GSEC is responsible for the formation of N-terminal APP amyloid-β (Aβ) peptides of different length (e.g., Aβ42) that can form aggregates involved in Alzheimer's disease pathogenesis. The molecular mechanism of GSEC-APP substrate recognition is key for understanding how different peptide products are formed and could help in designing APP-selective modulators. Based on the known structure of apo GSEC and the APP-C99 fragment we have generated putative structural models of the initial binding in three different possible modes using extensive molecular dynamics (MD) simulations. The binding mode with the substrate helix located in a cleft between the transmembrane helices 2 and 3 of the presenilin subunit was identified as a most likely binding mode. Based on this arrangement, the processing steps were investigated using restraint MD simulations to pull the scissile bond (for each processing step) into a transition like (cleavable) state. This allowed us to analyze in detail the motions and energetic contributions of participating residues. The structural model agrees qualitatively well with the influence of many mutations in GSEC and C99. It also explains the effects of inhibitors, cross-linking, as well as spectroscopic data on GSEC substrate binding and can serve as working model for the future planning of structural and biochemical studies.
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Affiliation(s)
- M. Hitzenberger
- Physics Department T38, Technical University of Munich, James-Frank-Str. 1, 85748 Garching, Germany
| | - M. Zacharias
- Physics Department T38, Technical University of Munich, James-Frank-Str. 1, 85748 Garching, Germany
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18
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Das A, Narayanam MK, Paul S, Mukhnerjee P, Ghosh S, Dastidar DG, Chakrabarty S, Ganguli A, Basu B, Pal M, Chatterji U, Banerjee SK, Karmakar P, Kumar D, Chakrabarti G. A novel triazole, NMK-T-057, induces autophagic cell death in breast cancer cells by inhibiting γ-secretase-mediated activation of Notch signaling. J Biol Chem 2019; 294:6733-6750. [PMID: 30824542 DOI: 10.1074/jbc.ra119.007671] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Indexed: 01/05/2023] Open
Abstract
Notch signaling is reported to be deregulated in several malignancies, including breast, and the enzyme γ-secretase plays an important role in the activation and nuclear translocation of Notch intracellular domain (NICD). Hence, pharmacological inhibition of γ-secretase might lead to the subsequent inhibition of Notch signaling in cancer cells. In search of novel γ-secretase inhibitors (GSIs), we screened a series of triazole-based compounds for their potential to bind γ-secretase and observed that 3-(3'4',5'-trimethoxyphenyl)-5-(N-methyl-3'-indolyl)-1,2,4-triazole compound (also known as NMK-T-057) can bind to γ-secretase complex. Very interestingly, NMK-T-057 was found to inhibit proliferation, colony-forming ability, and motility in various breast cancer (BC) cells such as MDA-MB-231, MDA-MB-468, 4T1 (triple-negative cells), and MCF-7 (estrogen receptor (ER)/progesterone receptor (PR)-positive cell line) with negligible cytotoxicity against noncancerous cells (MCF-10A and peripheral blood mononuclear cells). Furthermore, significant induction of apoptosis and inhibition of epithelial-to-mesenchymal transition (EMT) and stemness were also observed in NMK-T-057-treated BC cells. The in silico study revealing the affinity of NMK-T-057 toward γ-secretase was further validated by a fluorescence-based γ-secretase activity assay, which confirmed inhibition of γ-secretase activity in NMK-T-057-treated BC cells. Interestingly, it was observed that NMK-T-057 induced significant autophagic responses in BC cells, which led to apoptosis. Moreover, NMK-T-057 was found to inhibit tumor progression in a 4T1-BALB/c mouse model. Hence, it may be concluded that NMK-T-057 could be a potential drug candidate against BC that can trigger autophagy-mediated cell death by inhibiting γ-secretase-mediated activation of Notch signaling.
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Affiliation(s)
- Amlan Das
- From the Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and .,Department of Chemistry, National Institute of Technology, Ravangla, South Sikkim 737139, India
| | - Maruthi Kumar Narayanam
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, Rajasthan 333031, India.,Department of Molecular and Medical Pharmacology and Crump Institute for Molecular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, and
| | - Santanu Paul
- From the Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and
| | - Pritha Mukhnerjee
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Suvranil Ghosh
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Road, Scheme VIIM, Kankurgachi, Kolkata 700054, West Bengal, India
| | - Debabrata Ghosh Dastidar
- From the Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and.,Division of Pharmaceutics, Guru Nanak Institute of Pharmaceutical Science and Technology, 157/F Nilgunj Road, Panihati, Kolkata 700114, West Bengal, India
| | - Subhendu Chakrabarty
- From the Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and
| | - Arnab Ganguli
- From the Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and
| | - Biswarup Basu
- Department of Experimental Hematology and Neuroendocrinology, Chittaranjan National Cancer Institute, 37 Shyama Prasad Mukherjee Road, Kolkata 700026, West Bengal, India
| | - Mahadeb Pal
- Division of Molecular Medicine, Bose Institute, P-1/12, CIT Road, Scheme VIIM, Kankurgachi, Kolkata 700054, West Bengal, India
| | - Urmi Chatterji
- Department of Zoology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata 700019, West Bengal, India
| | - Sushanta K Banerjee
- Cancer Research Unit, Veterans Affairs Medical Center, Kansas City, Missouri 64128.,Departments of Anatomy and Cell Biology and Pathology, University of Kansas Medical Center, Kansas City, Kansas 66160
| | - Parimal Karmakar
- Department of Life Science and Biotechnology, Jadavpur University, 188 Raja S. C. Mullick Road, Kolkata 700032, Western Bengal, India
| | - Dalip Kumar
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, Rajasthan 333031, India,
| | - Gopal Chakrabarti
- From the Department of Biotechnology and Dr. B. C. Guha Centre for Genetic Engineering and Biotechnology and
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19
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Hitzenberger M, Zacharias M. γ-Secretase Studied by Atomistic Molecular Dynamics Simulations: Global Dynamics, Enzyme Activation, Water Distribution and Lipid Binding. Front Chem 2019; 6:640. [PMID: 30662893 PMCID: PMC6328467 DOI: 10.3389/fchem.2018.00640] [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: 09/28/2018] [Accepted: 12/07/2018] [Indexed: 11/14/2022] Open
Abstract
γ-secretase, an intramembrane-cleaving aspartyl protease is involved in the cleavage of a large number of intramembrane proteins. The most prominent substrate is the amyloid precursor protein, whose proteolytic processing leads to the production of different amyloid Aβ peptides. These peptides are known to form toxic aggregates and may play a key role in Alzheimer's disease (AD). Recently, the three-dimensional structure of γ-secretase has been determined via Cryo-EM, elucidating the spatial geometry of this enzyme complex in different functional states. We have used molecular dynamics (MD) simulations to study the global dynamics and conformational transitions of γ-secretase, as well as the water and lipid distributions in and around the transmembrane domains in atomic detail. Simulations were performed on the full enzyme complex and on the membrane embedded parts alone. The simulations revealed global motions compatible with the experimental enzyme structures and indicated little dependence of the dynamics of the transmembrane domains on the soluble extracellular subunits. During the simulation on the membrane spanning part a transition between an inactive conformation (with catalytic residues far apart) toward a putatively active form (with catalytic residues in close proximity) has been observed. This conformational change is associated with a distinct rearrangement of transmembrane helices, a global compaction of the catalytically active presenilin subunit a change in the water structure near the active site and a rigidification of the protein fold. The observed conformational rearrangement allows the interpretation of the effect of several mutations on the activity of γ-secretase. A number of long-lived lipid binding sites could be identified on the membrane spanning surface of γ-secretase which may coincide with association regions of hydrophobic membrane helices to form putative substrate binding exosites.
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Affiliation(s)
| | - Martin Zacharias
- Physics Department T38, Technical University of Munich, Garching, Germany
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20
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Johnson DS, Li YM, Pettersson M, St George-Hyslop PH. Structural and Chemical Biology of Presenilin Complexes. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a024067. [PMID: 28320827 PMCID: PMC5710098 DOI: 10.1101/cshperspect.a024067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The presenilin proteins are the catalytic subunits of a tetrameric complex containing presenilin 1 or 2, anterior pharynx defective 1 (APH1), nicastrin, and PEN-2. Other components such as TMP21 may exist in a subset of specialized complexes. The presenilin complex is the founding member of a unique class of aspartyl proteases that catalyze the γ, ɛ, ζ site cleavage of the transmembrane domains of Type I membrane proteins including amyloid precursor protein (APP) and Notch. Here, we detail the structural and chemical biology of this unusual enzyme. Taken together, these studies suggest that the complex exists in several conformations, and subtle long-range (allosteric) shifts in the conformation of the complex underpin substrate access to the catalytic site and the mechanism of action for allosteric inhibitors and modulators. Understanding the mechanics of these shifts will facilitate the design of γ-secretase modulator (GSM) compounds that modulate the relative efficiency of γ, ɛ, ζ site cleavage and/or substrate specificity.
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Affiliation(s)
- Douglas S. Johnson
- Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139
| | - Yue-Ming Li
- Chemical Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065
| | - Martin Pettersson
- Pfizer Worldwide Research and Development, Cambridge, Massachusetts 02139
| | - Peter H. St George-Hyslop
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrookes Hospital, Cambridge CB2 0XY, United Kingdom,Tanz Centre for Research in Neurodegenerative Diseases and Departments of Medicine, Laboratory Medicine and Pathobiology, and Medical Biophysics, University of Toronto, Toronto, Ontario M5T 2S8, Canada
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Zhu B, Jiang L, Huang T, Zhao Y, Liu T, Zhong Y, Li X, Campos A, Pomeroy K, Masliah E, Zhang D, Xu H. ER-associated degradation regulates Alzheimer's amyloid pathology and memory function by modulating γ-secretase activity. Nat Commun 2017; 8:1472. [PMID: 29133892 PMCID: PMC5684335 DOI: 10.1038/s41467-017-01799-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 10/13/2017] [Indexed: 12/11/2022] Open
Abstract
Endoplasmic-reticulum-associated degradation (ERAD) is an important protein quality control system which maintains protein homeostasis. Constituents of the ERAD complex and its role in neurodegeneration are not yet fully understood. Here, using proteomic and FRET analyses, we demonstrate that the ER protein membralin is an ERAD component, which mediates degradation of ER luminal and membrane substrates. Interestingly, we identify nicastrin, a key component of the γ-secretase complex, as a membralin binding protein and membralin-associated ERAD substrate. We demonstrate a reduction of membralin mRNA and protein levels in Alzheimer's disease (AD) brain, the latter of which inversely correlates with nicastrin abundance. Furthermore, membralin deficiency enhances γ-secretase activity and neuronal degeneration. In a mouse AD model, downregulating membralin results in β-amyloid pathology, neuronal death, and exacerbates synaptic/memory deficits. Our results identify membralin as an ERAD component and demonstrate a critical role for ERAD in AD pathogenesis.
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Affiliation(s)
- Bing Zhu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - LuLin Jiang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Timothy Huang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Yingjun Zhao
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Tongfei Liu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Yongwang Zhong
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Xiaoguang Li
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Alexandre Campos
- Proteomics Facility, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Kenneth Pomeroy
- Proteomics Facility, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Eliezer Masliah
- Departments of Neurosciences and Pathology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Dongxian Zhang
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Huaxi Xu
- Neuroscience Initiative, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA.
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, 361005, Fujian, China.
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22
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Vossen A, van der Zee H, Prens E. Sequence variants in hidradenitis suppurativa: in search of the pathogenic mechanisms. Br J Dermatol 2017; 177:895-896. [DOI: 10.1111/bjd.15812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- A.R.J.V. Vossen
- Department of Dermatology; Erasmus University Medical Center; Rotterdam the Netherlands
| | - H.H. van der Zee
- Department of Dermatology; Erasmus University Medical Center; Rotterdam the Netherlands
| | - E.P. Prens
- Department of Dermatology; Erasmus University Medical Center; Rotterdam the Netherlands
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23
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Cai Z, Liu Z, Xiao M, Wang C, Tian F. Chronic Cerebral Hypoperfusion Promotes Amyloid-Beta Pathogenesis via Activating β/γ-Secretases. Neurochem Res 2017; 42:3446-3455. [DOI: 10.1007/s11064-017-2391-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/10/2017] [Accepted: 08/16/2017] [Indexed: 10/19/2022]
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SNX27 and SORLA Interact to Reduce Amyloidogenic Subcellular Distribution and Processing of Amyloid Precursor Protein. J Neurosci 2017; 36:7996-8011. [PMID: 27466343 DOI: 10.1523/jneurosci.0206-16.2016] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 06/09/2016] [Indexed: 01/10/2023] Open
Abstract
UNLABELLED Proteolytic generation of amyloidogenic amyloid β (Aβ) fragments from the amyloid precursor protein (APP) significantly contributes to Alzheimer's disease (AD). Although amyloidogenic APP proteolysis can be affected by trafficking through genetically associated AD components such as SORLA, how SORLA functionally interacts with other trafficking components is yet unclear. Here, we report that SNX27, an endosomal trafficking/recycling factor and a negative regulator of the γ-secretase complex, binds to the SORLA cytosolic tail to form a ternary complex with APP. SNX27 enhances cell surface SORLA and APP levels in human cell lines and mouse primary neurons, and depletion of SNX27 or SORLA reduces APP endosome-to-cell surface recycling kinetics. SNX27 overexpression enhances the generation of cell surface APP cleavage products such as soluble alpha-APP C-terminal fragment (CTFα) in a SORLA-dependent manner. SORLA-mediated Aβ reduction is attenuated by downregulation of SNX27. This indicates that an SNX27/SORLA complex functionally interacts to limit APP distribution to amyloidogenic compartments, forming a non-amyloidogenic shunt to promote APP recycling to the cell surface. SIGNIFICANCE STATEMENT Many genes have been identified as risk factors for Alzheimer's disease (AD), and a large proportion of these genes function to limit production or toxicity of the AD-associated amyloid β (Aβ) peptide. Whether and how these genes precisely operate to limit AD onset remains an important question. We identify binding and trafficking interactions between two of these factors, SORLA and SNX27, and demonstrate that SNX27 can direct trafficking of SORLA and the Aβ precursor APP to the cell surface to limit the production of Aβ. Diversion APP to the cell surface through modulation of this molecular complex may represent a complimentary strategy for future development in AD treatment.
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Nicastrin functions to sterically hinder γ-secretase-substrate interactions driven by substrate transmembrane domain. Proc Natl Acad Sci U S A 2015; 113:E509-18. [PMID: 26699478 DOI: 10.1073/pnas.1512952113] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
γ-Secretase is an intramembrane-cleaving protease that processes many type-I integral membrane proteins within the lipid bilayer, an event preceded by shedding of most of the substrate's ectodomain by α- or β-secretases. The mechanism by which γ-secretase selectively recognizes and recruits ectodomain-shed substrates for catalysis remains unclear. In contrast to previous reports that substrate is actively recruited for catalysis when its remaining short ectodomain interacts with the nicastrin component of γ-secretase, we find that substrate ectodomain is entirely dispensable for cleavage. Instead, γ-secretase-substrate binding is driven by an apparent tight-binding interaction derived from substrate transmembrane domain, a mechanism in stark contrast to rhomboid--another family of intramembrane-cleaving proteases. Disruption of the nicastrin fold allows for more efficient cleavage of substrates retaining longer ectodomains, indicating that nicastrin actively excludes larger substrates through steric hindrance, thus serving as a molecular gatekeeper for substrate binding and catalysis.
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26
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Sparling DP, Yu J, Kim K, Zhu C, Brachs S, Birkenfeld AL, Pajvani UB. Adipocyte-specific blockade of gamma-secretase, but not inhibition of Notch activity, reduces adipose insulin sensitivity. Mol Metab 2015; 5:113-121. [PMID: 26909319 PMCID: PMC4735659 DOI: 10.1016/j.molmet.2015.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 11/18/2015] [Accepted: 11/25/2015] [Indexed: 01/12/2023] Open
Abstract
Objective As the obesity pandemic continues to expand, novel molecular targets to reduce obesity-related insulin resistance and Type 2 Diabetes (T2D) continue to be needed. We have recently shown that obesity is associated with reactivated liver Notch signaling, which, in turn, increases hepatic insulin resistance, opening up therapeutic avenues for Notch inhibitors to be repurposed for T2D. Herein, we tested the systemic effects of γ-secretase inhibitors (GSIs), which prevent endogenous Notch activation, and confirmed these effects through creation and characterization of two different adipocyte-specific Notch loss-of-function mouse models through genetic ablation of the Notch transcriptional effector Rbp-Jk (A-Rbpj) and the obligate γ-secretase component Nicastrin (A-Nicastrin). Methods Glucose homeostasis and both local adipose and systemic insulin sensitivity were examined in GSI-treated, A-Rbpj and A-Nicastrin mice, as well as vehicle-treated or control littermates, with complementary in vitro studies in primary hepatocytes and 3T3-L1 adipocytes. Results GSI-treatment increases hepatic insulin sensitivity in obese mice but leads to reciprocal lowering of adipose glucose disposal. While A-Rbpj mice show normal body weight, adipose development and mass and unchanged adipose insulin sensitivity as control littermates, A-Nicastrin mice are relatively insulin-resistant, mirroring the GSI effect on adipose insulin action. Conclusions Notch signaling is dispensable for normal adipocyte function, but adipocyte-specific γ-secretase blockade reduces adipose insulin sensitivity, suggesting that specific Notch inhibitors would be preferable to GSIs for application in T2D. γ-secretase inhibitors (GSIs) are non-specific inhibitors of Notch signaling. GSI-treatment of obese mice increases hepatic, but lowers adipose insulin sensitivity. Adipocyte-specific Notch inhibition does not affect adipose mass or glucose homeostasis. Adipocyte-specific γ-secretase blockade reduces adipose insulin sensitivity. Specific Notch inhibitors may be preferable to GSIs for treatment of Type 2 Diabetes.
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Affiliation(s)
- David P Sparling
- Departments of Pediatrics, Columbia University, New York, NY 10032, USA
| | - Junjie Yu
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - KyeongJin Kim
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Changyu Zhu
- Department of Medicine, Columbia University, New York, NY 10032, USA
| | - Sebastian Brachs
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
| | - Andreas L Birkenfeld
- Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), a member of the German Center for Diabetes Research (DZD), Technische Universität Dresden, Germany; Section of Diabetes and Nutritional Sciences, Rayne Institute, Denmark Hill Campus, King's College London, UK
| | - Utpal B Pajvani
- Department of Medicine, Columbia University, New York, NY 10032, USA.
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Joshi G, Bekier ME, Wang Y. Golgi fragmentation in Alzheimer's disease. Front Neurosci 2015; 9:340. [PMID: 26441511 PMCID: PMC4585163 DOI: 10.3389/fnins.2015.00340] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 09/08/2015] [Indexed: 11/24/2022] Open
Abstract
The Golgi apparatus is an essential cellular organelle for post-translational modifications, sorting, and trafficking of membrane and secretory proteins. Proper functionality of the Golgi requires the formation of its unique cisternal-stacking morphology. The Golgi structure is disrupted in a variety of neurodegenerative diseases, suggesting a common mechanism and contribution of Golgi defects in neurodegenerative disorders. A recent study on Alzheimer's disease (AD) revealed that phosphorylation of the Golgi stacking protein GRASP65 disrupts its function in Golgi structure formation, resulting in Golgi fragmentation. Inhibiting GRASP65 phosphorylation restores the Golgi morphology from Aβ-induced fragmentation and reduces Aβ production. Perturbing Golgi structure and function in neurons may directly impact trafficking, processing, and sorting of a variety of proteins essential for synaptic and dendritic integrity. Therefore, Golgi defects may ultimately promote the development of AD. In the current review, we focus on the cellular impact of impaired Golgi morphology and its potential relationship to AD disease development.
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Affiliation(s)
- Gunjan Joshi
- Department of Molecular, Cellular and Developmental Biology, University of Michigan Ann Arbor, MI, USA
| | - Michael E Bekier
- Department of Molecular, Cellular and Developmental Biology, University of Michigan Ann Arbor, MI, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan Ann Arbor, MI, USA ; Department of Neurology, University of Michigan School of Medicine Ann Arbor, MI, USA
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28
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Feng T, Niu M, Ji C, Gao Y, Wen J, Bu G, Xu H, Zhang YW. SNX15 Regulates Cell Surface Recycling of APP and Aβ Generation. Mol Neurobiol 2015; 53:3690-3701. [PMID: 26115702 DOI: 10.1007/s12035-015-9306-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 06/16/2015] [Indexed: 12/31/2022]
Abstract
Amyloid-β (Aβ) peptide plays an essential role in the pathogenesis of Alzheimer's disease (AD) and is generated from amyloid-β precursor protein (APP) through sequential proteolytic cleavages by β-site APP cleaving enzyme 1 (BACE1) and γ-secretase. Trafficking dysregulation of APP, BACE1, and γ-secretase may affect Aβ generation and disease pathogenesis. Sorting nexin 15 (SNX15) is known to regulate protein trafficking. Here, we report that SNX15 is abundantly expressed in mouse neurons and astrocytes. In addition, we show that although not affecting the protein levels of APP, BACE1, and γ-secretase components and the activity of BACE1 and γ-secretase, overexpression and downregulation of SNX15 reduce and promote Aβ production, respectively. Furthermore, we find that overexpression of SNX15 increases APP protein levels in cell surface through accelerating APP recycling, whereas downregulation of SNX15 has an opposite effect. Finally, we show that exogenous expression of human SNX15 in the hippocampal dentate gyrus by adeno-associated virus (AAV) infection can significantly reduce Aβ pathology in the hippocampus and improve short-term working memory in the APPswe/PSEN1dE9 double transgenic AD model mice. Together, our results suggest that SNX15 regulates the recycling of APP to cell surface and, thus, its processing for Aβ generation.
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Affiliation(s)
- Tuancheng Feng
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, College of Medicine, Xiamen University, Xiamen, 361102, China
| | - Mengmeng Niu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, College of Medicine, Xiamen University, Xiamen, 361102, China
| | - Chengxiang Ji
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, College of Medicine, Xiamen University, Xiamen, 361102, China
| | - Yuehong Gao
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, College of Medicine, Xiamen University, Xiamen, 361102, China
| | - Jing Wen
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, College of Medicine, Xiamen University, Xiamen, 361102, China
| | - Guojun Bu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, College of Medicine, Xiamen University, Xiamen, 361102, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, College of Medicine, Xiamen University, Xiamen, 361102, China
- Degenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, CA, 92037, USA
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, School of Pharmaceutical Sciences, College of Medicine, Xiamen University, Xiamen, 361102, China.
- Degenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, CA, 92037, USA.
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29
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Bekris LM, Tsuang DW, Peskind ER, Yu CE, Montine TJ, Zhang J, Zabetian CP, Leverenz JB. Cerebrospinal fluid Aβ42 levels and APP processing pathway genes in Parkinson's disease. Mov Disord 2015; 30:936-44. [PMID: 25808939 DOI: 10.1002/mds.26172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 12/22/2014] [Accepted: 12/29/2014] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Of recent interest is the finding that certain cerebrospinal fluid (CSF) biomarkers traditionally linked to Alzheimer's disease (AD), specifically amyloid beta protein (Aβ), are abnormal in PD CSF. The aim of this exploratory investigation was to determine whether genetic variation within the amyloid precursor protein (APP) processing pathway genes correlates with CSF Aβ42 levels in Parkinson's disease (PD). METHODS Parkinson's disease (n = 86) and control (n = 161) DNA were genotyped for 19 regulatory region tagging single-nucleotide polymorphisms (SNPs) within nine genes (APP, ADAM10, BACE1, BACE2, PSEN1, PSEN2, PEN2, NCSTN, and APH1B) involved in the cleavage of APP. The SNP genotypes were tested for their association with CSF biomarkers and PD risk while adjusting for age, sex, and APOE ɛ4 status. RESULTS Significant correlation with CSF Aβ42 levels in PD was observed for two SNPs, (APP rs466448 and APH1B rs2068143). Conversely, significant correlation with CSF Aβ42 levels in controls was observed for three SNPs (APP rs214484, rs2040273, and PSEN1 rs362344). CONCLUSIONS In addition, results of this exploratory investigation suggest that an APP SNP and an APH1B SNP are marginally associated with PD CSF Aβ42 levels in APOE ɛ4 noncarriers. Further hypotheses generated include that decreased CSF Aβ42 levels are in part driven by genetic variation in APP processing genes. Additional investigation into the relationship between these findings and clinical characteristics of PD, including cognitive impairment, compared with other neurodegenerative diseases, such as AD, are warranted. © 2015 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Lynn M Bekris
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Debby W Tsuang
- Northwest Network Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA
| | - Elaine R Peskind
- Northwest Network Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA
| | - Chang E Yu
- Geriatric Research, Education, and Clinical Center (GRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Thomas J Montine
- Northwest Network Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA.,Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.,Northwest Network Parkinson's Disease Research, Education and Clinical Center (PADRECC), VA Puget Sound Health Care System, Seattle, Washington, USA
| | - Jing Zhang
- Northwest Network Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA.,Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.,Northwest Network Parkinson's Disease Research, Education and Clinical Center (PADRECC), VA Puget Sound Health Care System, Seattle, Washington, USA
| | - Cyrus P Zabetian
- Geriatric Research, Education, and Clinical Center (GRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA.,Northwest Network Parkinson's Disease Research, Education and Clinical Center (PADRECC), VA Puget Sound Health Care System, Seattle, Washington, USA
| | - James B Leverenz
- Lou Ruvo Center for Brain Health, Neurological Institute, Cleveland Clinic, Cleveland, Ohio, USA
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30
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Acne Inversa Caused by Missense Mutations in NCSTN Is Not Fully Compatible with Impairments in Notch Signaling. J Invest Dermatol 2015; 135:618-620. [DOI: 10.1038/jid.2014.399] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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31
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Li Y, Bohm C, Dodd R, Chen F, Qamar S, Schmitt-Ulms G, Fraser PE, St George-Hyslop PH. Structural biology of presenilin 1 complexes. Mol Neurodegener 2014; 9:59. [PMID: 25523933 PMCID: PMC4326451 DOI: 10.1186/1750-1326-9-59] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/12/2014] [Indexed: 11/17/2022] Open
Abstract
The presenilin genes were first identified as the site of missense mutations causing early onset autosomal dominant familial Alzheimer's disease. Subsequent work has shown that the presenilin proteins are the catalytic subunits of a hetero-tetrameric complex containing APH1, nicastrin and PEN-2. This complex (variously termed presenilin complex or gamma-secretase complex) performs an unusual type of proteolysis in which the transmembrane domains of Type I proteins are cleaved within the hydrophobic compartment of the membrane. This review describes some of the molecular and structural biology of this unusual enzyme complex. The presenilin complex is a bilobed structure. The head domain contains the ectodomain of nicastrin. The base domain contains a central cavity with a lateral cleft that likely provides the route for access of the substrate to the catalytic cavity within the centre of the base domain. There are reciprocal allosteric interactions between various sites in the complex that affect its function. For instance, binding of Compound E, a peptidomimetic inhibitor to the PS1 N-terminus, induces significant conformational changes that reduces substrate binding at the initial substrate docking site, and thus inhibits substrate cleavage. However, there is a reciprocal allosteric interaction between these sites such that prior binding of the substrate to the initial docking site paradoxically increases the binding of the Compound E peptidomimetic inhibitor. Such reciprocal interactions are likely to form the basis of a gating mechanism that underlies access of substrate to the catalytic site. An increasingly detailed understanding of the structural biology of the presenilin complex is an essential step towards rational design of substrate- and/or cleavage site-specific modulators of presenilin complex function.
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Affiliation(s)
| | | | | | | | | | | | | | - Peter H St George-Hyslop
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrookes Hospital, Hills Road, Cambridge CB2 0XY, UK.
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32
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Zhang X, Li Y, Xu H, Zhang YW. The γ-secretase complex: from structure to function. Front Cell Neurosci 2014; 8:427. [PMID: 25565961 PMCID: PMC4263104 DOI: 10.3389/fncel.2014.00427] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 11/27/2014] [Indexed: 12/21/2022] Open
Abstract
One of the most critical pathological features of Alzheimer’s disease (AD) is the accumulation of β-amyloid (Aβ) peptides that form extracellular senile plaques in the brain. Aβ is derived from β-amyloid precursor protein (APP) through sequential cleavage by β- and γ-secretases. γ-secretase is a high molecular weight complex minimally composed of four components: presenilins (PS), nicastrin, anterior pharynx defective 1 (APH-1), and presenilin enhancer 2 (PEN-2). In addition to APP, γ-secretase also cleaves many other type I transmembrane (TM) protein substrates. As a crucial enzyme for Aβ production, γ-secretase is an appealing therapeutic target for AD. Here, we summarize current knowledge on the structure and function of γ-secretase, as well as recent progress in developing γ-secretase targeting drugs for AD treatment.
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Affiliation(s)
- Xian Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, FJ, China
| | - Yanfang Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, FJ, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, FJ, China ; Degenerative Disease Research Program, Sanford-Burnham Medical Research Institute La Jolla, CA, USA
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University Xiamen, FJ, China
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33
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Alexander AG, Marfil V, Li C. Use of Caenorhabditis elegans as a model to study Alzheimer's disease and other neurodegenerative diseases. Front Genet 2014; 5:279. [PMID: 25250042 PMCID: PMC4155875 DOI: 10.3389/fgene.2014.00279] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 07/31/2014] [Indexed: 12/12/2022] Open
Abstract
Advances in research and technology has increased our quality of life, allowed us to combat diseases, and achieve increased longevity. Unfortunately, increased longevity is accompanied by a rise in the incidences of age-related diseases such as Alzheimer’s disease (AD). AD is the sixth leading cause of death, and one of the leading causes of dementia amongst the aged population in the USA. It is a progressive neurodegenerative disorder, characterized by the prevalence of extracellular Aβ plaques and intracellular neurofibrillary tangles, derived from the proteolysis of the amyloid precursor protein (APP) and the hyperphosphorylation of microtubule-associated protein tau, respectively. Despite years of extensive research, the molecular mechanisms that underlie the pathology of AD remain unclear. Model organisms, such as the nematode, Caenorhabditis elegans, present a complementary approach to addressing these questions. C. elegans has many advantages as a model system to study AD and other neurodegenerative diseases. Like their mammalian counterparts, they have complex biochemical pathways, most of which are conserved. Genes in which mutations are correlated with AD have counterparts in C. elegans, including an APP-related gene, apl-1, a tau homolog, ptl-1, and presenilin homologs, such as sel-12 and hop-1. Since the neuronal connectivity in C. elegans has already been established, C. elegans is also advantageous in modeling learning and memory impairments seen during AD. This article addresses the insights C. elegans provide in studying AD and other neurodegenerative diseases. Additionally, we explore the advantages and drawbacks associated with using this model.
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Affiliation(s)
- Adanna G Alexander
- Department of Biology, City College of New York New York, NY, USA ; Department of Biology, The Graduate Center, City University of New York New York, NY, USA
| | - Vanessa Marfil
- Department of Biology, City College of New York New York, NY, USA
| | - Chris Li
- Department of Biology, City College of New York New York, NY, USA ; Department of Biology, The Graduate Center, City University of New York New York, NY, USA
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Abstract
γ-Secretase is an intramembrane protease responsible for the generation of amyloid-β (Aβ) peptides. Aberrant accumulation of Aβ leads to the formation of amyloid plaques in the brain of patients with Alzheimer's disease. Nicastrin is the putative substrate-recruiting component of the γ-secretase complex. No atomic-resolution structure had been identified on γ-secretase or any of its four components, hindering mechanistic understanding of γ-secretase function. Here we report the crystal structure of nicastrin from Dictyostelium purpureum at 1.95-Å resolution. The extracellular domain of nicastrin contains a large lobe and a small lobe. The large lobe of nicastrin, thought to be responsible for substrate recognition, associates with the small lobe through a hydrophobic pivot at the center. The putative substrate-binding pocket is shielded from the small lobe by a lid, which blocks substrate entry. These structural features suggest a working model of nicastrin function. Analysis of nicastrin structure provides insights into the assembly and architecture of the γ-secretase complex.
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Signaling pathways in breast cancer: therapeutic targeting of the microenvironment. Cell Signal 2014; 26:2843-56. [PMID: 25093804 DOI: 10.1016/j.cellsig.2014.07.034] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 07/28/2014] [Indexed: 02/08/2023]
Abstract
Breast cancer is the most common cancer in women worldwide. Understanding the biology of this malignant disease is a prerequisite for selecting an appropriate treatment. Cell cycle alterations are seen in many cancers, including breast cancer. Newly popular targeted agents in breast cancer include cyclin dependent kinase inhibitors (CDKIs) which are agents inhibiting the function of cyclin dependent kinases (CDKs) and agents targeting proto-oncogenic signaling pathways like Notch, Wnt, and SHH (Sonic hedgehog). CDKIs are categorized as selective and non-selective inhibitors of CDK. CDKIs have been tried as monotherapy and combination therapy. The CDKI Palbocyclib is now a promising therapeutic in breast cancer. This drug recently entered phase III trial for estrogen receptor (ER) positive breast cancer after showing encouraging results in progression free survival in a phase II trials. The tumor microenvironment is now recognized as a significant factor in cancer treatment response. The tumor microenvironment is increasingly considered as a target for combination therapy of breast cancer. Recent findings in the signaling pathways in breast cancer are herein summarized and discussed. Furthermore, the therapeutic targeting of the microenvironment in breast cancer is also considered.
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36
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Wang L, Hu J, Zhao Y, Lu X, Zhang Q, Niu Q. Effects of aluminium on β-amyloid (1-42) and secretases (APP-cleaving enzymes) in rat brain. Neurochem Res 2014; 39:1338-45. [PMID: 24792732 DOI: 10.1007/s11064-014-1317-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2013] [Revised: 04/16/2014] [Accepted: 04/21/2014] [Indexed: 01/22/2023]
Abstract
Chronic administration of aluminium has been proposed as an environmental factor that may affect some pathological changes related to neurotoxicity and Alzheimer's disease (AD). The abnormal generation and deposition of β-amyloid (Aβ) in senile plaques are hallmark features in the brains of AD patients. Furthermore, Aβ is generated by the sequential cleavage of the amyloid precursor protein (APP) via the APP cleaving enzyme (α-secretase, or β-secretase) and γ-secretase. In the present study, we investigated the modulation of Aβ deposition and neurotoxicity in aluminium-maltolate-treated (0, 15, 30, 45 mmol/kg body weight via intraperitoneal injection) in experimental rats. We measured Aβ1-40 and Aβ1-42 in the cortex and hippocampus in rat brains using ELISA. Subtypes of α-secretase, β-secretase, and γ-secretase, including ADAM9, ADAM10, ADAM17 (TACE), BACE1, presenilin 1 (PS1) and nicastrin (NCT), were determined using western blotting analyses. These results indicated that aluminium-maltolate induced an AD-like behavioural deficit in rats at 30 and 45 mmol/kg body weight. Moreover, the Aβ1-42 content increased significantly, both in the cortex and hippocampus, although no changes were observed in Aβ1-40. Furthermore, ADAM9, ADAM10, and ADAM17 decreased significantly; in contrast, BACE1, PS1, and NCT showed significant increase. Taken together, these results suggest that the changes in secretases may correlate to the abnormal deposition of Aβ by aluminium in rat brains.
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Affiliation(s)
- Linping Wang
- School of Public Health, Shanxi Medical University, Taiyuan, 030001, Shanxi, China
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Peltonen HM, Haapasalo A, Hiltunen M, Kataja V, Kosma VM, Mannermaa A. Γ-secretase components as predictors of breast cancer outcome. PLoS One 2013; 8:e79249. [PMID: 24223915 PMCID: PMC3815159 DOI: 10.1371/journal.pone.0079249] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 09/19/2013] [Indexed: 12/26/2022] Open
Abstract
γ-secretase is a large ubiquitously expressed protease complex composed of four core subunits: presenilin, Aph1, PEN-2, and nicastrin. The function of γ-secretase in the cells is to proteolytically cleave various proteins within their transmembrane domains. Presenilin and Aph1 occur as alternative variants belonging to mutually exclusive γ-secretase complexes and providing the complexes with heterogeneous biochemical and physiological properties. γ-secretase is proposed to have a role in the development and progression of cancer and γ-secretase inhibitors are intensively studied for their probable anti-tumor effects in various types of cancer models. Here, we for the first time determined mRNA expression levels of presenilin-1, presenilin-2, Aph1a, Aph1b, PEN-2, and nicastrin in a set of breast cancer tissue samples (N = 55) by quantitative real-time PCR in order to clarify the clinical significance of the expression of different γ-secretase complex components in breast cancer. We found a high positive correlation between the subunit expression levels implying a common regulation of transcription. Our univariate Kaplan-Meier survival analyses established low expression level of γ-secretase complex as a risk factor for breast cancer specific mortality. The tumors expressing low levels of γ-secretase complex were characterized by high histopathological tumor grade, low or no expression of estrogen and progesterone receptors and consequently high probability to fall into the class of triple negative breast cancer tumors. These results may provide novel tools to further categorize breast cancer tumors, especially the highly aggressive and poorly treatable breast cancer type of triple negative cases, and suggest a significant role for γ-secretase in breast cancer.
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Affiliation(s)
- Hanna M. Peltonen
- Institute of Clinical Medicine, Pathology and Forensic Medicine, University of Eastern Finland, Kuopio, Finland
- Biocenter Kuopio and Cancer Center of Eastern Finland, University of Eastern Finland, Kuopio, Finland
- Imaging Center, Clinical Pathology, Kuopio University Hospital, Kuopio, Finland
- * E-mail:
| | - Annakaisa Haapasalo
- Institute of Clinical Medicine – Neurology, University of Eastern Finland, Kuopio, Finland
| | - Mikko Hiltunen
- Institute of Clinical Medicine – Neurology, University of Eastern Finland, Kuopio, Finland
| | - Vesa Kataja
- Institute of Clinical Medicine, Oncology, University of Eastern Finland, Kuopio, Finland
- Cancer Center, Kuopio University Hospital, Kuopio, Finland
| | - Veli-Matti Kosma
- Institute of Clinical Medicine, Pathology and Forensic Medicine, University of Eastern Finland, Kuopio, Finland
- Biocenter Kuopio and Cancer Center of Eastern Finland, University of Eastern Finland, Kuopio, Finland
- Imaging Center, Clinical Pathology, Kuopio University Hospital, Kuopio, Finland
| | - Arto Mannermaa
- Institute of Clinical Medicine, Pathology and Forensic Medicine, University of Eastern Finland, Kuopio, Finland
- Biocenter Kuopio and Cancer Center of Eastern Finland, University of Eastern Finland, Kuopio, Finland
- Imaging Center, Clinical Pathology, Kuopio University Hospital, Kuopio, Finland
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Abstract
Notch signaling is an evolutionarily conserved cell signaling pathway involved in cell fate during development, stem cell renewal and differentiation in postnatal tissues. Roles for Notch in carcinogenesis, in the biology of cancer stem cells and tumor angiogenesis have been reported. These features identify Notch as a potential therapeutic target in oncology. Based on the molecular structure of Notch receptor, Notch ligands and Notch activators, a set of Notch pathway inhibitors have been developed. Most of these inhibitors had shown anti-tumor effects in preclinical studies. At the same time, the combinatorial effect of these inhibitors with current chemotherapeutical drugs is still under study in different clinical trials. In this review, we describe the basics of Notch signaling and the role of Notch in normal and cancer stem cells as a logic way to develop different Notch inhibitors and their current stage of progress for cancer patient's treatment.
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Affiliation(s)
- Ingrid Espinoza
- University of Mississippi, Cancer Institute, Jackson, Mississippi
| | - Lucio Miele
- University of Mississippi, Cancer Institute, Jackson, Mississippi
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Li X, Liu Y, Zheng Q, Yao G, Cheng P, Bu G, Xu H, Zhang YW. Ferritin light chain interacts with PEN-2 and affects γ-secretase activity. Neurosci Lett 2013; 548:90-4. [PMID: 23685131 DOI: 10.1016/j.neulet.2013.05.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/15/2013] [Accepted: 05/08/2013] [Indexed: 11/17/2022]
Abstract
Alzheimer's disease (AD) is primarily caused by overproduction/deposition of β-amyloid (Aβ) in the brain. Dysregulation of iron in the brain also contributes to AD. Although iron affects β-amyloid precursor protein (APP) expression and Aβ deposition, detailed role of iron in AD requires further elucidation. Aβ is produced by sequential proteolytic cleavages of APP by β-secretase and γ-secretase. The γ-secretase complex comprises presenilins (PS1 or PS2), nicastrin, APH-1, and PEN-2. Herein, we find that PEN-2 can interact with ferritin light chain (FTL), an important component of the iron storage protein ferritin. In addition, we show that overexpression of FTL increases the protein levels of PEN-2 and PS1 amino-terminal fragment (NTF) and promotes γ-secretase activity for more production of Aβ and notch intracellular domain (NICD). Furthermore, iron treatments increase the levels of FTL, PEN-2 and PS1 NTF and promote γ-secretase-mediated NICD production. Moreover, downregulation of FTL decreases the levels of PEN-2 and PS1 NTF. Together, our results suggest that iron can increase γ-secretase activity through promoting the level of FTL that interacts with and stabilizes PEN-2, providing a new molecular link between iron, PEN-2/γ-secretase and Aβ generation in AD.
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Affiliation(s)
- Xinxin Li
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, Fujian 361102, People's Republic of China
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40
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Alterations in gene expression in mutant amyloid precursor protein transgenic mice lacking Niemann-Pick type C1 protein. PLoS One 2013; 8:e54605. [PMID: 23382922 PMCID: PMC3558508 DOI: 10.1371/journal.pone.0054605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 12/14/2012] [Indexed: 12/19/2022] Open
Abstract
Niemann-Pick type C (NPC) disease, a rare autosomal recessive disorder caused mostly by mutation in NPC1 gene, is pathologically characterized by the accumulation of free cholesterol in brain and other tissues. This is accompanied by gliosis and loss of neurons in selected brain regions, including the cerebellum. Recent studies have shown that NPC disease exhibits intriguing parallels with Alzheimer’s disease, including the presence of neurofibrillary tangles and increased levels of amyloid precursor protein (APP)-derived β-amyloid (Aβ) peptides in vulnerable brain neurons. To evaluate the role of Aβ in NPC disease, we determined the gene expression profile in selected brain regions of our recently developed bigenic ANPC mice, generated by crossing APP transgenic (Tg) mice with heterozygous Npc1-deficient mice. The ANPC mice exhibited exacerbated neuronal and glial pathology compared to other genotypes [i.e., APP-Tg, double heterozygous (Dhet), Npc1-null and wild-type mice]. Analysis of expression profiles of 86 selected genes using real-time RT-PCR arrays showed a wide-spectrum of alterations in the four genotypes compared to wild-type controls. The changes observed in APP-Tg and Dhet mice are limited to only few genes involved mostly in the regulation of cholesterol metabolism, whereas Npc1-null and ANPC mice showed alterations in the expression profiles of a number of genes regulating cholesterol homeostasis, APP metabolism, vesicular trafficking and cell death mechanism in both hippocampus and cerebellum compared to wild-type mice. Intriguingly, ANPC and Npc1-null mice, with some exceptions, exhibited similar changes, although more genes were differentially expressed in the affected cerebellum than the relatively spared hippocampus. The altered gene profiles were found to match with the corresponding protein levels. These results suggest that lack of Npc1 protein can alter the expression profile of selected transcripts as well as proteins, and APP overexpression influences cerebral pathology by enhancing changes triggered by Npc1 deficiency in the bigenic line.
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Membrane proteases in the bacterial protein secretion and quality control pathway. Microbiol Mol Biol Rev 2012; 76:311-30. [PMID: 22688815 DOI: 10.1128/mmbr.05019-11] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Proteolytic cleavage of proteins that are permanently or transiently associated with the cytoplasmic membrane is crucially important for a wide range of essential processes in bacteria. This applies in particular to the secretion of proteins and to membrane protein quality control. Major progress has been made in elucidating the structure-function relationships of many of the responsible membrane proteases, including signal peptidases, signal peptide hydrolases, FtsH, the rhomboid protease GlpG, and the site 1 protease DegS. These enzymes employ very different mechanisms to cleave substrates at the cytoplasmic and extracytoplasmic membrane surfaces or within the plane of the membrane. This review highlights the different ways that bacterial membrane proteases degrade their substrates, with special emphasis on catalytic mechanisms and substrate delivery to the respective active sites.
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42
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Nicastrin regulates breast cancer stem cell properties and tumor growth in vitro and in vivo. Proc Natl Acad Sci U S A 2012; 109:16558-63. [PMID: 23012411 DOI: 10.1073/pnas.1206268109] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nicastrin (NCT) is a crucial component of the γ-secretase (GS) enzyme, which prompted investigations into its biological role in cancer. We have previously shown that nicastrin is overexpressed in breast cancer (BC), conferring worse overall survival in invasive, ERα negative patients. Here, we used 2D and 3D Matrigel, anchorage-independent growth conditions and a breast cancer xenograft mouse model to assess the impact of nicastrin on breast cancer stem cell (BCSC) propagation and invasion in vitro and tumor growth in vivo. Stable knockdown of nicastrin in HCC1806 breast cancer cells reduced cell invasion by 51.4 ± 1.7%, accompanied by a morphological change to a rounded cell phenotype and down-regulation of vimentin, Snail, Twist, MMP2, and MMP9. We observed a reduction of the pool of CD44(+)/CD24(-) and ALDH1 high breast cancer stem cells by threefold and twofold, respectively, and a reduction by 2.6-fold of the mammospheres formation. Nicastrin overexpression in nontransformed MCF10A cells caused an induction of epithelial to mesenchymal regulators, as well as a fivefold increased ALDH1 activity, a threefold enrichment for CD44(+)/CD24(-) stem cells, and a 3.2-fold enhanced mammosphere-forming capacity. Using the γ-sescretase inhibiton, Notch1/4 siRNA, and Akt inhibition, we show that nicastrin regulates breast cancer stem cells partly through Notch1 and the Akt pathway. Exploiting serial dilution transplantation of the HCC1806 cells expressing nicastrin and HCC1806 stably depleted of nicastrin, in vivo, we demonstrate that nicastrin inhibition may be relevant for the reduced tumorigenicity of breast cancer cells. These data could serve as a benchmark for development of nicastrin-targeted therapies in breast cancer.
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Gael B, Georgakopoulos A, Robakis NK. Cellular mechanisms of γ-secretase substrate selection, processing and toxicity. Prog Neurobiol 2012; 98:166-75. [PMID: 22622135 PMCID: PMC3404154 DOI: 10.1016/j.pneurobio.2012.05.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/12/2012] [Accepted: 05/08/2012] [Indexed: 01/04/2023]
Abstract
Presenilins (PSs) are catalytic components of the γ-secretase proteolytic complexes that produce Aβ and cell signaling peptides. γ-Secretase substrates are mostly membrane-bound peptides derived following proteolytic cleavage of the extracellular domain of type I transmembrane proteins. Recent work reveals that γ-secretase substrate processing is regulated by proteins termed γ-secretase substrate recruiting factors (γSSRFs) that bridge substrates to γ-secretase complexes. These factors constitute novel targets for pharmacological control of specific γ-secretase products, such as Aβ and signaling peptides. PS familial Alzheimer's disease (FAD) mutants cause a loss of γ-secretase cleavage function at epsilon sites of substrates thus inhibiting production of cell signaling peptides while promoting accumulation of uncleaved toxic substrates. Importantly, γ-secretase inhibitors may cause toxicity in vivo by similar mechanisms. Here we review novel mechanisms that control γ-secretase substrate selection and cleavage and examine their relevance to AD.
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Affiliation(s)
- Barthet Gael
- Center for Molecular Biology and Genetics of Neurodegeneration, Departments of Psychiatry and Neuroscience, Mount Sinai School of Medicine, New York, NY 10029
| | - Anastasios Georgakopoulos
- Center for Molecular Biology and Genetics of Neurodegeneration, Departments of Psychiatry and Neuroscience, Mount Sinai School of Medicine, New York, NY 10029
| | - Nikolaos K. Robakis
- Center for Molecular Biology and Genetics of Neurodegeneration, Departments of Psychiatry and Neuroscience, Mount Sinai School of Medicine, New York, NY 10029
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44
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Hamilton G, Killick R, Lambert JC, Amouyel P, Carrasquillo MM, Pankratz VS, Graff-Radford NR, Dickson DW, Petersen RC, Younkin SG, Powell JF, Wade-Martins R. Functional and genetic analysis of haplotypic sequence variation at the nicastrin genomic locus. Neurobiol Aging 2012; 33:1848.e1-13. [PMID: 22405046 PMCID: PMC3683320 DOI: 10.1016/j.neurobiolaging.2012.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 01/19/2012] [Accepted: 02/04/2012] [Indexed: 11/23/2022]
Abstract
Nicastrin (NCSTN) is a component of the γ-secretase complex and therefore potentially a candidate risk gene for Alzheimer's disease. Here, we have developed a novel functional genomics methodology to express common locus haplotypes to assess functional differences. DNA recombination was used to engineer 5 bacterial artificial chromosomes (BACs) to each express a different haplotype of the NCSTN locus. Each NCSTN-BAC was delivered to knockout nicastrin (Ncstn(-/-)) cells and clonal NCSTN-BAC(+)/Ncstn(-/-) cell lines were created for functional analyses. We showed that all NCSTN-BAC haplotypes expressed nicastrin protein and rescued γ-secretase activity and amyloid beta (Aβ) production in NCSTN-BAC(+)/Ncstn(-/-) lines. We then showed that genetic variation at the NCSTN locus affected alternative splicing in human postmortem brain tissue. However, there was no robust functional difference between clonal cell lines rescued by each of the 5 different haplotypes. Finally, there was no statistically significant association of NCSTN with disease risk in the 4 cohorts. We therefore conclude that it is unlikely that common variation at the NCSTN locus is a risk factor for Alzheimer's disease.
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Affiliation(s)
- Gillian Hamilton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
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45
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Identification of a tetratricopeptide repeat-like domain in the nicastrin subunit of γ-secretase using synthetic antibodies. Proc Natl Acad Sci U S A 2012; 109:8534-9. [PMID: 22586122 DOI: 10.1073/pnas.1202691109] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The γ-secretase complex, composed of presenilin, anterior-pharynx-defective 1, nicastrin, and presenilin enhancer 2, catalyzes the intramembranous processing of a wide variety of type I membrane proteins, including amyloid precursor protein (APP) and Notch. Earlier studies have revealed that nicastrin, a type I membrane-anchored glycoprotein, plays a role in γ-secretase assembly and trafficking and has been proposed to bind substrates. To gain more insights regarding nicastrin structure and function, we generated a conformation-specific synthetic antibody and used it as a molecular probe to map functional domains within nicastrin ectodomain. The antibody bound to a conformational epitope within a nicastrin segment encompassing residues 245-630 and inhibited the processing of APP and Notch substrates in in vitro γ-secretase activity assays, suggesting that a functional domain pertinent to γ-secretase activity resides within this region. Epitope mapping and database searches revealed the presence of a structured segment, located downstream of the previously identified DAP domain (DYIGS and peptidase; residues 261-502), that is homologous to a tetratricopeptide repeat (TPR) domain commonly involved in peptide recognition. Mutagenesis analyses within the predicted TPR-like domain showed that disruption of the signature helical structure resulted in the loss of γ-secretase activity but not the assembly of the γ-secretase and that Leu571 within the TPR-like domain plays an important role in mediating substrate binding. Taken together, these studies offer provocative insights pertaining to the structural basis for nicastrin function as a "substrate receptor" within the γ-secretase complex.
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46
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Mo JS, Yoon JH, Hong JA, Kim MY, Ann EJ, Ahn JS, Kim SM, Baek HJ, Lang F, Choi EJ, Park HS. Phosphorylation of nicastrin by SGK1 leads to its degradation through lysosomal and proteasomal pathways. PLoS One 2012; 7:e37111. [PMID: 22590650 PMCID: PMC3349648 DOI: 10.1371/journal.pone.0037111] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 04/13/2012] [Indexed: 12/18/2022] Open
Abstract
The gamma-secretase complex is involved in the intramembranous proteolysis of a variety of substrates, including the amyloid precursor protein and the Notch receptor. Nicastrin (NCT) is an essential component of the gamma-secretase complex and functions as a receptor for gamma-secretase substrates. In this study, we determined that serum- and glucocorticoid-induced protein kinase 1 (SGK1) markedly reduced the protein stability of NCT. The SGK1 kinase activity was decisive for NCT degradation and endogenous SGK1 inhibited gamma-secretase activity. SGK1 downregulates NCT protein levels via proteasomal and lysosomal pathways. Furthermore, SGK1 directly bound to and phosphorylated NCT on Ser437, thereby promoting protein degradation. Collectively, our findings indicate that SGK1 is a gamma-secretase regulator presumably effective through phosphorylation and degradation of NCT.
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Affiliation(s)
- Jung-Soon Mo
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Ji-Hye Yoon
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Ji-Ae Hong
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Mi-Yeon Kim
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Eun-Jung Ann
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Ji-Seon Ahn
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Su-Man Kim
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Hyeong-Jin Baek
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
| | - Florian Lang
- Department of Physiology, University of Tübingen, Tübingen, Germany
| | - Eui-Ju Choi
- School of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Hee-Sae Park
- School of Biological Sciences and Technology, Hormone Research Center, Chonnam National University, Gwangju, Republic of Korea
- * E-mail:
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47
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Fluhrer R, Kamp F, Grammer G, Nuscher B, Steiner H, Beyer K, Haass C. The Nicastrin ectodomain adopts a highly thermostable structure. Biol Chem 2012; 392:995-1001. [PMID: 21848507 DOI: 10.1515/bc.2011.169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Nicastrin is a type I transmembrane glycoprotein, which is part of the high molecular weight γ-secretase complex. γ-Secretase is one of the key players associated with the generation of Alzheimer's disease pathology, since it liberates the neurotoxic amyloid β-peptide. Four proteins Nicastrin, anterior pharynx-defective-1 (Aph-1), presenilin enhancer-2 (Pen-2) and Presenilin are essential to form the active γ-secretase complex. Recently it has been shown, that Nicastrin has a key function in stabilizing the mature γ-secretase complex and may also be involved in substrate recognition. So far no structural data for the Nicastrin ectodomain or any other γ-secretase component are available. We therefore used Circular Dichroism (CD) spectroscopy to demonstrate that Nicastrin, similar to its homologues, the Streptomyces griseus aminopeptidase (SGAP) and the transferrin receptor (TfR), adopts a thermostable secondary structure. Furthermore, the Nicastrin ectodomain has an exceptionally high propensity to refold after thermal denaturation. These findings provide evidence to further support the hypothesis that Nicastrin may share evolutionary conserved properties with the aminopeptidase and the transferrin receptor family.
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Affiliation(s)
- Regina Fluhrer
- Adolf-Butenandt-Institute, Biochemistry, Ludwig Maximilians University, Schillerstrasse 44, 80336 Munich, Germany
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48
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Zhang H, Ma Q, Zhang YW, Xu H. Proteolytic processing of Alzheimer's β-amyloid precursor protein. J Neurochem 2011; 120 Suppl 1:9-21. [PMID: 22122372 DOI: 10.1111/j.1471-4159.2011.07519.x] [Citation(s) in RCA: 231] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
β-Amyloid precursor protein (APP) is a critical factor in the pathogenesis of Alzheimer's disease (AD). APP undergoes post-translational proteolysis/processing to generate the hydrophobic β-amyloid (Aβ) peptides. Deposition of Aβ in the brain, forming oligomeric Aβ and plaques, is identified as one of the key pathological hallmarks of AD. The processing of APP to generate Aβ is executed by β- and γ-secretase and is highly regulated. Aβ toxicity can lead to synaptic dysfunction, neuronal cell death, impaired learning/memory and abnormal behaviors in AD models in vitro and in vivo. Aside from Aβ, proteolytic cleavages of APP can also give rise to the APP intracellular domain, reportedly involved in multiple types of cellular events such as gene transcription and apoptotic cell death. In addition to amyloidogenic processing, APP can also be cleaved by α-secretase to form a soluble or secreted APP ectodomain (sAPP-α) that has been shown to be mostly neuro-protective. In this review, we describe the mechanisms involved in APP metabolism and the likely functions of its various proteolytic products to give a better understanding of the patho/physiological functions of APP.
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Affiliation(s)
- Han Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, College of Medicine, Xiamen University, Xiamen, Fujian, China.,Neurodegenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Qilin Ma
- Department of Neurology, The First Affiliated Hospital of Xiamen University, Xiamen, Fujian, China
| | - Yun-Wu Zhang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, College of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Huaxi Xu
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, College of Medicine, Xiamen University, Xiamen, Fujian, China.,Neurodegenerative Disease Research Program, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
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49
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Fraering PC. Structural and Functional Determinants of gamma-Secretase, an Intramembrane Protease Implicated in Alzheimer's Disease. Curr Genomics 2011; 8:531-49. [PMID: 19415127 PMCID: PMC2647162 DOI: 10.2174/138920207783769521] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 12/27/2007] [Accepted: 12/27/2007] [Indexed: 12/28/2022] Open
Abstract
Alzheimer’s disease is the most common form of neurodegenerative diseases in humans, characterized by the progressive accumulation and aggregation of amyloid-β peptides (Aβ) in brain regions subserving memory and cognition. These 39-43 amino acids long peptides are generated by the sequential proteolytic cleavages of the amyloid-β precursor protein (APP) by β- and γ-secretases, with the latter being the founding member of a new class of intramembrane-cleaving proteases (I-CliPs) characterized by their intramembranous catalytic residues hydrolyzing the peptide bonds within the transmembrane regions of their respective substrates. These proteases include the S2P family of metalloproteases, the Rhomboid family of serine proteases, and two aspartyl proteases: the signal peptide peptidase (SPP) and γ-secretase. In sharp contrast to Rhomboid and SPP that function as a single component, γ-secretase is a multi-component protease with complex assembly, maturation and activation processes. Recently, two low-resolution three-dimensional structures of γ-secretase and three high-resolution structures of the GlpG rhomboid protease have been obtained almost simultaneously by different laboratories. Although these proteases are unrelated by sequence or evolution, they seem to share common functional and structural mechanisms explaining how they catalyze intramembrane proteolysis. Indeed, a water-containing chamber in the catalytic cores of both γ-secretase and GlpG rhomboid provides the hydrophilic environment required for proteolysis and a lateral gating mechanism controls substrate access to the active site. The studies that have identified and characterized the structural determinants critical for the assembly and activity of the γ-secretase complex are reviewed here.
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Affiliation(s)
- Patrick C Fraering
- Brain Mind Institute and School of Life Sciences, Swiss Federal Institute of Technology (EPFL), CH-1015 Lausanne, Switzerland
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Marutani T, Maeda T, Tanabe C, Zou K, Araki W, Kokame K, Michikawa M, Komano H. ER-stress-inducible Herp, facilitates the degradation of immature nicastrin. Biochim Biophys Acta Gen Subj 2011; 1810:790-8. [PMID: 21600962 DOI: 10.1016/j.bbagen.2011.04.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 03/29/2011] [Accepted: 04/29/2011] [Indexed: 11/29/2022]
Abstract
BACKGROUND Herp is an endoplasmic reticulum (ER)-stress-inducible membrane protein harboring an ubiquitin-like domain (ULD). However, its biological functions are not fully understood. Here, we examined the role of Herp in the degradation of γ-secretase components. METHODS Effects of ULD-lacking Herp (ΔUb-Herp) expression on the degradation of γ-secretase components were analyzed. RESULTS The cellular expression of ΔUb-Herp was found to inhibit the degradation of overexpressed immature nicastrin and full-length presenilin. The mechanisms underlying Herp-mediated nicastrin degradation was further analyzed. We found that immature nicastrin accumulates in the ER of ΔUb-Herp overexpressing cells or Herp-deficient cells more than that in the ER of wild-type cells. Further, ΔUb-Herp expression inhibited nicastrin ubiquitination, suggesting that the ULD of Herp is likely involved in nicastrin ubiquitination. Co-immunoprecipitation study showed that Herp as well as ΔUb-Herp potentially interacts with nicastrin, mediating nicastrin interaction with p97, which functions in retranslocation of misfolded proteins from the ER to the cytosol. CONCLUSIONS Thus, Herp is likely involved in degradation of immature nicastrin by facilitating p97-dependent nicastrin retranslocation and ubiquitination. GENERAL SIGNIFICANCE We suggest that Herp could play a role in the elimination of the excess unassembled components of a multimeric complex.
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Affiliation(s)
- Toshihiro Marutani
- Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan
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