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Devkota S, Zhou R, Nagarajan V, Maesako M, Do H, Noorani A, Overmeyer C, Bhattarai S, Douglas JT, Saraf A, Miao Y, Ackley BD, Shi Y, Wolfe MS. Familial Alzheimer mutations stabilize synaptotoxic γ-secretase-substrate complexes. Cell Rep 2024; 43:113761. [PMID: 38349793 PMCID: PMC10941010 DOI: 10.1016/j.celrep.2024.113761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/19/2023] [Accepted: 01/24/2024] [Indexed: 02/15/2024] Open
Abstract
Mutations that cause familial Alzheimer's disease (FAD) are found in amyloid precursor protein (APP) and presenilin, the catalytic component of γ-secretase, that together produce amyloid β-peptide (Aβ). Nevertheless, whether Aβ is the primary disease driver remains controversial. We report here that FAD mutations disrupt initial proteolytic events in the multistep processing of APP substrate C99 by γ-secretase. Cryoelectron microscopy reveals that a substrate mimetic traps γ-secretase during the transition state, and this structure aligns with activated enzyme-substrate complex captured by molecular dynamics simulations. In silico simulations and in cellulo fluorescence microscopy support stabilization of enzyme-substrate complexes by FAD mutations. Neuronal expression of C99 and/or presenilin-1 in Caenorhabditis elegans leads to synaptic loss only with FAD-mutant transgenes. Designed mutations that stabilize the enzyme-substrate complex and block Aβ production likewise led to synaptic loss. Collectively, these findings implicate the stalled process-not the products-of γ-secretase cleavage of substrates in FAD pathogenesis.
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Affiliation(s)
- Sujan Devkota
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, USA
| | - Rui Zhou
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | | | - Masato Maesako
- Alzheimer Research Unit, MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Hung Do
- Center for Computational Biology, University of Kansas, Lawrence, KS, USA
| | - Arshad Noorani
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, USA
| | - Caitlin Overmeyer
- Graduate Program in Neurosciences, University of Kansas, Lawrence, KS, USA
| | - Sanjay Bhattarai
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, USA
| | - Justin T Douglas
- Nuclear Magnetic Resonance Core Lab, University of Kansas, Lawrence, KS, USA
| | - Anita Saraf
- Mass Spectrometry and Analytical Proteomic Laboratory, University of Kansas, Lawrence, KS, USA
| | - Yinglong Miao
- Center for Computational Biology, University of Kansas, Lawrence, KS, USA; Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA
| | - Brian D Ackley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, USA
| | - Yigong Shi
- Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China; Westlake Laboratory of Life Science and Biomedicine, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, and Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang Province, China
| | - Michael S Wolfe
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS, USA; Graduate Program in Neurosciences, University of Kansas, Lawrence, KS, USA.
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Montenegro P, Chen P, Kang J, Lee SH, Leone S, Shen J. Human Presenilin-1 delivered by AAV9 rescues impaired γ-secretase activity, memory deficits, and neurodegeneration in Psen mutant mice. Proc Natl Acad Sci U S A 2023; 120:e2306714120. [PMID: 37816062 PMCID: PMC10589670 DOI: 10.1073/pnas.2306714120] [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: 04/28/2023] [Accepted: 09/06/2023] [Indexed: 10/12/2023] Open
Abstract
Mutations in the Presenilin (PSEN1 and PSEN2) genes are the major cause of early-onset familial Alzheimer's disease (FAD). Presenilin (PS) is the catalytic subunit of the γ-secretase complex, which cleaves type I transmembrane proteins, such as Notch and the amyloid precursor protein (APP), and plays an evolutionarily conserved role in the protection of neuronal survival during aging. FAD PSEN1 mutations exhibit impaired γ-secretase activity in cell culture, in vitro, and knockin (KI) mouse brains, and the L435F mutation is the most severe in reducing γ-secretase activity and is located closest to the active site of γ-secretase. Here, we report that introduction of the codon-optimized wild-type human PSEN1 cDNA by adeno-associated virus 9 (AAV9) results in broadly distributed, sustained, low to moderate levels of human PS1 (hPS1) expression and rescues impaired γ-secretase activity in the cerebral cortex of Psen mutant mice either lacking PS or expressing the Psen1 L435F KI allele, as evaluated by endogenous γ-secretase substrates of APP and recombinant γ-secretase products of Notch intracellular domain and Aβ peptides. Furthermore, introduction of hPS1 by AAV9 alleviates impairments of synaptic plasticity and learning and memory in Psen mutant mice. Importantly, AAV9 delivery of hPS1 ameliorates neurodegeneration in the cerebral cortex of aged Psen mutant mice, as shown by the reversal of age-dependent loss of cortical neurons and elevated microgliosis and astrogliosis. These results together show that moderate hPS1 expression by AAV9 is sufficient to rescue impaired γ-secretase activity, synaptic and memory deficits, and neurodegeneration caused by Psen mutations in mouse models.
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Affiliation(s)
- Paola Montenegro
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
| | - Phoenix Chen
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
| | - Jongkyun Kang
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
| | - Sang Hun Lee
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
| | - Sofia Leone
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
| | - Jie Shen
- Department of Neurology, Brigham and Women’s Hospital, Boston, MA02115
- Program in Neuroscience, Harvard Medical School, Boston, MA02115
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Kurth V, Ogorek I, Münch C, Lopez-Rios J, Ousson S, Lehmann S, Nieweg K, Roebroek AJM, Pietrzik CU, Beher D, Weggen S. Pathogenic Aβ production by heterozygous PSEN1 mutations is intrinsic to the mutant protein and not mediated by conformational hindrance of wild-type PSEN1. J Biol Chem 2023; 299:104997. [PMID: 37394008 PMCID: PMC10413157 DOI: 10.1016/j.jbc.2023.104997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 05/30/2023] [Accepted: 06/07/2023] [Indexed: 07/04/2023] Open
Abstract
Presenilin-1 (PSEN1) is the catalytic subunit of the intramembrane protease γ-secretase and undergoes endoproteolysis during its maturation. Heterozygous mutations in the PSEN1 gene cause early-onset familial Alzheimer's disease (eFAD) and increase the proportion of longer aggregation-prone amyloid-β peptides (Aβ42 and/or Aβ43). Previous studies had suggested that PSEN1 mutants might act in a dominant-negative fashion by functional impediment of wild-type PSEN1, but the exact mechanism by which PSEN1 mutants promote pathogenic Aβ production remains controversial. Using dual recombinase-mediated cassette exchange (dRMCE), here we generated a panel of isogenic embryonic and neural stem cell lines with heterozygous, endogenous expression of PSEN1 mutations. When catalytically inactive PSEN1 was expressed alongside the wild-type protein, we found the mutant accumulated as a full-length protein, indicating that endoproteolytic cleavage occurred strictly as an intramolecular event. Heterozygous expression of eFAD-causing PSEN1 mutants increased the Aβ42/Aβ40 ratio. In contrast, catalytically inactive PSEN1 mutants were still incorporated into the γ-secretase complex but failed to change the Aβ42/Aβ40 ratio. Finally, interaction and enzyme activity assays demonstrated the binding of mutant PSEN1 to other γ-secretase subunits, but no interaction between mutant and wild-type PSEN1 was observed. These results establish that pathogenic Aβ production is an intrinsic property of PSEN1 mutants and strongly argue against a dominant-negative effect in which PSEN1 mutants would compromise the catalytic activity of wild-type PSEN1 through conformational effects.
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Affiliation(s)
- Vanessa Kurth
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Isabella Ogorek
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany; Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Carolina Münch
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Javier Lopez-Rios
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-Universidad Pablo de Olavide-Junta de Andalucia, Sevilla, Spain
| | | | - Sandra Lehmann
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany
| | - Katja Nieweg
- Institute of Pharmacology and Clinical Pharmacy, Philipps-University, Marburg, Germany
| | | | - Claus U Pietrzik
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | | | - Sascha Weggen
- Department of Neuropathology, Heinrich Heine University, Düsseldorf, Germany.
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Ji YM, Hou M, Zhou W, Ning ZW, Zhang Y, Xing GW. An AIE-Active NIR Fluorescent Probe with Good Water Solubility for the Detection of Aβ 1-42 Aggregates in Alzheimer's Disease. Molecules 2023; 28:5110. [PMID: 37446772 DOI: 10.3390/molecules28135110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/25/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
Alzheimer's disease (AD), an amyloid-related disease, seriously endangers the health of elderly individuals. According to current research, its main pathogenic factor is the amyloid protein, which is a kind of fibrillar aggregate formed by noncovalent self-assembly of proteins. Based on the characteristics of aggregation-induced emission (AIE), a bislactosyl-decorated tetraphenylethylene (TPE) molecule TMNL (TPE + malononitrile + lactose), bearing two malononitrile substituents, was designed and synthesized in this work. The amphiphilic TMNL could self-assemble into fluorescent organic nanoparticles (FONs) with near-infrared (NIR) fluorescence emission in physiological PBS (phosphate buffered saline), achieving excellent fluorescent enhancement (47-fold) upon its combination with Aβ1-42 fibrils. TMNL was successfully applied to image Aβ1-42 plaques in the brain tissue of AD transgenic mice, and due to the AIE properties of TMNL, no additional rinsing process was necessary. It is believed that the probe reported in this work should be useful for the sensitive detection and accurate localization mapping of Aβ1-42 aggregates related to Alzheimer's disease.
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Affiliation(s)
- Yan-Ming Ji
- Center of Safety Production and Testing Technology, China Academy of Safety Science and Technology, Beijing 100012, China
| | - Min Hou
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wei Zhou
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Zhang-Wei Ning
- College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Yuan Zhang
- College of Chemistry, Beijing Normal University, Beijing 100875, China
- Key Laboratory of Energy Conversion and Storage Materials, Beijing Normal University, Beijing 100875, China
| | - Guo-Wen Xing
- College of Chemistry, Beijing Normal University, Beijing 100875, China
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing 100875, China
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Lardelli M. An Alternative View of Familial Alzheimer's Disease Genetics. J Alzheimers Dis 2023; 96:13-39. [PMID: 37718800 DOI: 10.3233/jad-230313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2023]
Abstract
Probabilistic and parsimony-based arguments regarding available genetics data are used to propose that Hardy and Higgin's amyloid cascade hypothesis is valid but is commonly interpreted too narrowly to support, incorrectly, the primacy of the amyloid-β peptide (Aβ) in driving Alzheimer's disease pathogenesis. Instead, increased activity of the βCTF (C99) fragment of AβPP is the critical pathogenic determinant altered by mutations in the APP gene. This model is consistent with the regulation of APP mRNA translation via its 5' iron responsive element. Similar arguments support that the pathological effects of familial Alzheimer's disease mutations in the genes PSEN1 and PSEN2 are not exerted directly via changes in AβPP cleavage to produce different ratios of Aβ length. Rather, these mutations likely act through effects on presenilin holoprotein conformation and function, and possibly the formation and stability of multimers of presenilin holoprotein and/or of the γ-secretase complex. All fAD mutations in APP, PSEN1, and PSEN2 likely find unity of pathological mechanism in their actions on endolysosomal acidification and mitochondrial function, with detrimental effects on iron homeostasis and promotion of "pseudo-hypoxia" being of central importance. Aβ production is enhanced and distorted by oxidative stress and accumulates due to decreased lysosomal function. It may act as a disease-associated molecular pattern enhancing oxidative stress-driven neuroinflammation during the cognitive phase of the disease.
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Affiliation(s)
- Michael Lardelli
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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Barthelson K, Dong Y, Newman M, Lardelli M. PRESENILIN 1 Mutations Causing Early-Onset Familial Alzheimer's Disease or Familial Acne Inversa Differ in Their Effects on Genes Facilitating Energy Metabolism and Signal Transduction. J Alzheimers Dis 2021; 82:327-347. [PMID: 34024832 DOI: 10.3233/jad-210128] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The most common cause of early-onset familial Alzheimer's disease (EOfAD) is mutations in PRESENILIN 1 (PSEN1) allowing production of mRNAs encoding full-length, but mutant, proteins. In contrast, a single known frameshift mutation in PSEN1 causes familial acne inversa (fAI) without EOfAD. The molecular consequences of heterozygosity for these mutation types, and how they cause completely different diseases, remains largely unexplored. OBJECTIVE To analyze brain transcriptomes of young adult zebrafish to identify similarities and differences in the effects of heterozygosity for psen1 mutations causing EOfAD or fAI. METHODS RNA sequencing was performed on mRNA isolated from the brains of a single family of 6-month-old zebrafish siblings either wild type or possessing a single, heterozygous EOfAD-like or fAI-like mutation in their endogenous psen1 gene. RESULTS Both mutations downregulate genes encoding ribosomal subunits, and upregulate genes involved in inflammation. Genes involved in energy metabolism appeared significantly affected only by the EOfAD-like mutation, while genes involved in Notch, Wnt and neurotrophin signaling pathways appeared significantly affected only by the fAI-like mutation. However, investigation of direct transcriptional targets of Notch signaling revealed possible increases in γ-secretase activity due to heterozygosity for either psen1 mutation. Transcriptional adaptation due to the fAI-like frameshift mutation was evident. CONCLUSION We observed both similar and contrasting effects on brain transcriptomes of the heterozygous EOfAD-like and fAI-like mutations. The contrasting effects may illuminate how these mutation types cause distinct diseases.
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Affiliation(s)
- Karissa Barthelson
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, SA, Australia
| | - Yang Dong
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, SA, Australia
| | - Morgan Newman
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, SA, Australia
| | - Michael Lardelli
- Alzheimer's Disease Genetics Laboratory, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, SA, Australia
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Uddin MS, Hasana S, Hossain MF, Islam MS, Behl T, Perveen A, Hafeez A, Ashraf GM. Molecular Genetics of Early- and Late-Onset Alzheimer's Disease. Curr Gene Ther 2021; 21:43-52. [PMID: 33231156 DOI: 10.2174/1566523220666201123112822] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/17/2020] [Accepted: 10/19/2020] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly and this complex disorder is associated with environmental as well as genetic factors. Early-onset AD (EOAD) and late-onset AD (LOAD, more common) are major identified types of AD. The genetics of EOAD is extensively understood, with three gene variants such as APP, PSEN1, and PSEN2 leading to the disease. Some common alleles, including APOE, are effectively associated with LOAD identified, but the genetics of LOAD is not clear to date. It has been accounted that about 5-10% of EOAD patients can be explained through mutations in the three familiar genes of EOAD. The APOE ε4 allele augmented the severity of EOAD risk in carriers, and the APOE ε4 allele was considered as a hallmark of EOAD. A great number of EOAD patients, who are not genetically explained, indicate that it is not possible to identify disease-triggering genes yet. Although several genes have been identified by using the technology of next-generation sequencing in EOAD families, including SORL1, TYROBP, and NOTCH3. A number of TYROBP variants are identified through exome sequencing in EOAD patients and these TYROBP variants may increase the pathogenesis of EOAD. The existence of the ε4 allele is responsible for increasing the severity of EOAD. However, several ε4 allele carriers propose the presence of other LOAD genetic as well as environmental risk factors that are not identified yet. It is urgent to find out missing genetics of EOAD and LOAD etiology to discover new potential genetic facets which will assist in understanding the pathological mechanism of AD. These investigations should contribute to developing a new therapeutic candidate for alleviating, reversing and preventing AD. This article, based on current knowledge, represents the overview of the susceptible genes of EOAD, and LOAD. Next, we represent the probable molecular mechanism that might elucidate the genetic etiology of AD and highlight the role of massively parallel sequencing technologies for novel gene discoveries.
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Affiliation(s)
- Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh
| | - Sharifa Hasana
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh
| | | | | | - Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Chandigarh, India
| | - Asma Perveen
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Government College University, Faisalabad, Pakistan
| | - Abdul Hafeez
- Glocal School of Life Sciences, Glocal University, Saharanpur, India
| | - Ghulam Md Ashraf
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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Ayton S, Bush AI. β-amyloid: The known unknowns. Ageing Res Rev 2021; 65:101212. [PMID: 33188924 DOI: 10.1016/j.arr.2020.101212] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 12/11/2022]
Abstract
Alzheimer's disease (AD) stands out as a major disease without any form of preventative or disease modifying therapy. This is not for lack of trying. 33 phase 3 clinical trials of drugs targeting amyloid beta (Aβ) have failed to slow cognitive decline in AD. The field is at a cross-roads about whether to continue anti-Aβ therapy or more actively pursue alternative targets. With the burden of this disease to patients, families, and healthcare budgets growing yearly, the need for disease modifying AD therapies has become one of the highest priorities in all of medicine. While pathology, genetic and biochemical data offer a popular narrative for the causative role of Aβ, there are alternative explanations, and dissenting findings that, now more than ever, warrant thorough reanalysis. This review questions the major assumptions about Aβ on which therapies for AD were premised, and invites renewed interrogation into AD pathogenesis.
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Affiliation(s)
- Scott Ayton
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia.
| | - Ashley I Bush
- Melbourne Dementia Research Centre, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, 3052, Australia.
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Behl T, Kaur I, Fratila O, Brata R, Bungau S. Exploring the Potential of Therapeutic Agents Targeted towards Mitigating the Events Associated with Amyloid-β Cascade in Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21207443. [PMID: 33050199 PMCID: PMC7589257 DOI: 10.3390/ijms21207443] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/02/2020] [Accepted: 10/07/2020] [Indexed: 02/06/2023] Open
Abstract
One of the most commonly occurring neurodegenerative disorders, Alzheimer's disease (AD), encompasses the loss of cognitive and memory potential, impaired learning, dementia and behavioral defects, and has been prevalent since the 1900s. The accelerating occurrence of AD is expected to reach 65.7 million by 2030. The disease results in neural atrophy and disrupted inter-neuronal connections. Amongst multiple AD pathogenesis hypotheses, the amyloid beta (Aβ) cascade is the most relevant and accepted form of the hypothesis, which suggests that Aβ monomers are formed as a result of the cleavage of amyloid precursor protein (APP), followed by the conversion of these monomers to toxic oligomers, which in turn develop β-sheets, fibrils and plaques. The review targets the events in the amyloid hypothesis and elaborates suitable therapeutic agents that function by hindering the steps of plaque formation and lowering Aβ levels in the brain. The authors discuss treatment possibilities, including the inhibition of β- and γ-secretase-mediated enzymatic cleavage of APP, the immune response generating active immunotherapy and passive immunotherapeutic approaches targeting monoclonal antibodies towards Aβ aggregates, the removal of amyloid aggregates by the activation of enzymatic pathways or the regulation of Aβ circulation, glucagon-like peptide-1 (GLP-1)-mediated curbed accumulation and the neurotoxic potential of Aβ aggregates, bapineuzumab-mediated vascular permeability alterations, statin-mediated Aβ peptide degradation, the potential role of ibuprofen and the significance of natural drugs and dyes in hindering the amyloid cascade events. Thus, the authors aim to highlight the treatment perspective, targeting the amyloid hypothesis, while simultaneously emphasizing the need to conduct further investigations, in order to provide an opportunity to neurologists to develop novel and reliable treatment therapies for the retardation of AD progression.
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Affiliation(s)
- Tapan Behl
- Department of Pharmacology, Chitkara College of Pharmacy, Chitkara University, Punjab 140401, India;
- Correspondence: (T.B.); (S.B.); Tel.: +40-726-776-588 (S.B.)
| | - Ishnoor Kaur
- Department of Pharmacology, Chitkara College of Pharmacy, Chitkara University, Punjab 140401, India;
| | - Ovidiu Fratila
- Department of Medical Disciplines, Faculty of Medicine and Pharmacy, University of Oradea, Oradea 410073, Romania; (O.F.); (R.B.)
| | - Roxana Brata
- Department of Medical Disciplines, Faculty of Medicine and Pharmacy, University of Oradea, Oradea 410073, Romania; (O.F.); (R.B.)
| | - Simona Bungau
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, Oradea 410028, Romania
- Correspondence: (T.B.); (S.B.); Tel.: +40-726-776-588 (S.B.)
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10
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Wolfe MS. Unraveling the complexity of γ-secretase. Semin Cell Dev Biol 2020; 105:3-11. [PMID: 31980377 PMCID: PMC7371508 DOI: 10.1016/j.semcdb.2020.01.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/26/2019] [Accepted: 01/15/2020] [Indexed: 01/07/2023]
Abstract
γ-Secretase was initially defined as a proteolytic activity that cleaves within the transmembrane of the amyloid precursor protein (APP) to produce the amyloid β-peptide of Alzheimer's disease. The discovery of mutations in APP and the presenilins associated with familial Alzheimer's disease and their effects on APP processing dovetailed with pharmacological studies on γ-secretase, leading to the revelation that presenilins are unprecedented membrane-embedded aspartyl proteases. Other members of what became known as the γ-secretase complex were subsequently identified. In parallel with these advances, connections between presenilins and Notch receptors essential to metazoan development became evident, resulting in the concurrent realization that γ-secretase also carries out intramembrane proteolysis of Notch as part of its signaling mechanism. Substantial progress has been made toward elucidating how γ-secretase carries out complex processing of transmembrane domains, how it goes awry in familial Alzheimer's disease, the scope of its substrates, and the atomic details of its structure. Critical questions remain for future study, toward further unraveling the complexity of this unique membrane-embedded proteolytic machine and its roles in biology and disease.
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Affiliation(s)
- Michael S Wolfe
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66045, USA.
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11
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Naing SH, Oliver RC, Weiss KL, Urban VS, Lieberman RL. Solution Structure of an Intramembrane Aspartyl Protease via Small Angle Neutron Scattering. Biophys J 2019; 114:602-608. [PMID: 29414706 DOI: 10.1016/j.bpj.2017.12.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/04/2017] [Accepted: 12/18/2017] [Indexed: 12/14/2022] Open
Abstract
Intramembrane aspartyl proteases (IAPs) comprise one of four families of integral membrane proteases that hydrolyze substrates within the hydrophobic lipid bilayer. IAPs include signal peptide peptidase, which processes remnant signal peptides from nascent polypeptides in the endoplasmic reticulum, and presenilin, the catalytic component of the γ-secretase complex that processes Notch and amyloid precursor protein. Despite their broad biomedical reach, basic structure-function relationships of IAPs remain active areas of research. Characterization of membrane-bound proteins is notoriously challenging due to their inherently hydrophobic character. For IAPs, oligomerization state in solution is one outstanding question, with previous proposals for monomer, dimer, tetramer, and octamer. Here we used small angle neutron scattering (SANS) to characterize n-dodecyl-β-D-maltopyranoside (DDM) detergent solutions containing and absent a microbial IAP ortholog. A unique feature of SANS is the ability to modulate the solvent composition to mask all but the enzyme of interest. The signal from the IAP was enhanced by deuteration and, uniquely, scattering from DDM and buffers were matched by the use of both tail-deuterated DDM and D2O. The radius of gyration calculated for IAP and the corresponding ab initio consensus model are consistent with a monomer. The model is slightly smaller than the crystallographic IAP monomer, suggesting a more compact protein in solution compared with the crystal lattice. Our study provides direct insight into the oligomeric state of purified IAP in surfactant solution, and demonstrates the utility of fully contrast-matching the detergent in SANS to characterize other intramembrane proteases and their membrane-bound substrates.
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Affiliation(s)
- Swe-Htet Naing
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia
| | - Ryan C Oliver
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Kevin L Weiss
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Volker S Urban
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
| | - Raquel L Lieberman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia.
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12
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Madav Y, Wairkar S, Prabhakar B. Recent therapeutic strategies targeting beta amyloid and tauopathies in Alzheimer's disease. Brain Res Bull 2019; 146:171-184. [PMID: 30634016 DOI: 10.1016/j.brainresbull.2019.01.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/13/2018] [Accepted: 01/03/2019] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) has been a global concern for years due to its severe implications that affects the quality of life of the patients. The available line of therapy for treating Alzheimer's includes acetylcholinesterase inhibitors, NMDA(N-methyl-D-aspartate) antagonists and their combination which gives only symptomatic relief rather than treating the root cause of AD. Senile plaques and neurofibrillary tangles are the characteristic features underlying Alzheimer's pathology. Several attempts have been made towards exploring the niceties of these hallmarks and targeting various aspects of amyloid and tau pathology at different stages to eliminate the ultimate cause. Approaches targeting cleavage and formation of toxic amyloid fragments by secretases, aggregation of amyloid monofilaments, and immunotherapy against amyloid deposits has been extensively studied to treat amyloid pathology. Similarly, for tau pathology, tau hyperphosphorylation, microtubule stabilization, anti-tau immunotherapy has been explored. This article focuses on AD pathology and current pharmacotherapy, precisely for amyloid and tau. Furthermore, preclinical and clinical studies along with potential leads discovered under these approaches have also been included in this article. However, despite extensive research in drug development, overcoming clinical barrier still remain a major challenge for Alzheimer's pharmacotherapy.
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Affiliation(s)
- Yamini Madav
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKMs NMIMS, V.L.Mehta Road, Vile Parle (W), Mumbai, Maharashtra, 400056, India
| | - Sarika Wairkar
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKMs NMIMS, V.L.Mehta Road, Vile Parle (W), Mumbai, Maharashtra, 400056, India
| | - Bala Prabhakar
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKMs NMIMS, V.L.Mehta Road, Vile Parle (W), Mumbai, Maharashtra, 400056, India.
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13
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Wang X, Pei G. Visualization of Alzheimer's Disease Related α-/β-/γ-Secretase Ternary Complex by Bimolecular Fluorescence Complementation Based Fluorescence Resonance Energy Transfer. Front Mol Neurosci 2018; 11:431. [PMID: 30538620 PMCID: PMC6277482 DOI: 10.3389/fnmol.2018.00431] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/05/2018] [Indexed: 11/13/2022] Open
Abstract
The competitive ectodomain shedding of amyloid-β precursor protein (APP) by α-secretase and β-secretase, and the subsequent regulated intramembrane proteolysis by γ-secretase are the key processes in amyloid-β peptides (Aβ) generation. Previous studies indicate that secretases form binary complex and the interactions between secretases take part in substrates processing. However, whether α-, β- and γ-secretase could form ternary complex remains to be explored. Here, we adopted bimolecular fluorescence complementation in combination with fluorescence resonance energy transfer (BiFC-FRET) to visualize the formation of triple secretase complex. We show that the interaction between α-secretase ADAM10 and β-secretase BACE1 could be monitored by BiFC assay and the binding of APP to α-/β-secretase binary complex was revealed by BiFC-FRET. Further, we observed that γ-secretase interacts with α-/β-secretase binary complex, providing evidence that α-, β- and γ-secretase might form a ternary complex. Thus our study extends the interplay among Alzheimer's disease (AD) related α-/β-/γ-secretase.
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Affiliation(s)
- Xin Wang
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Gang Pei
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, and The Collaborative Innovation Center for Brain Science, Tongji University, Shanghai, China
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14
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Dai MH, Zheng H, Zeng LD, Zhang Y. The genes associated with early-onset Alzheimer's disease. Oncotarget 2018; 9:15132-15143. [PMID: 29599933 PMCID: PMC5871104 DOI: 10.18632/oncotarget.23738] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 10/14/2017] [Indexed: 01/31/2023] Open
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder that accounts for the most cases of dementia, which is characterized by the deposition of dense plaques of amyloid beta (Aβ) plaques and neurofibrillary tangles consisting of hyperphosphorylated tau. The two main types of AD can be classified as early-onset AD (EOAD, onset < 65 years) and late-onset AD (LOAD, onset ≥ 65 years). Evidence from family and twin studies indicate that genetic factors are estimated to play a role in at least 80% of AD cases. The first milestone with linkage analysis revealed the mutations in APP, PSEN1, and PSEN2 genes that cause EOAD. But pathogenic mutations in these three genes can only explain a small fraction of EOAD families. The additional disease-causing genes have not yet been identified. This review provides an overview of the genetic basis of EOAD and the relationship between the functions of these risk genes and the neuropathologic features of AD. A better understanding of genetic mechanisms underlying EOAD pathogenesis and the potentially molecular mechanisms of neurodegeneration will lead to the development of effective diagnosis and treatment strategies for this devastating disease.
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Affiliation(s)
- Meng-Hui Dai
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hui Zheng
- Department of Radiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Ling-Dan Zeng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yan Zhang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
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15
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Zhou R, Yang G, Shi Y. Dominant negative effect of the loss-of-function γ-secretase mutants on the wild-type enzyme through heterooligomerization. Proc Natl Acad Sci U S A 2017; 114:12731-12736. [PMID: 29078389 PMCID: PMC5715776 DOI: 10.1073/pnas.1713605114] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
γ-secretase is an intramembrane protease complex consisting of nicastrin, presenilin-1/2, APH-1a/b, and Pen-2. Hydrolysis of the 99-residue transmembrane fragment of amyloid precursor protein (APP-C99) by γ-secretase produces β-amyloid (Aβ) peptides. Pathogenic mutations in PSEN1 and PSEN2, which encode the catalytic subunit presenilin-1/2 of γ-secretase, lead to familial Alzheimer's disease in an autosomal dominant manner. However, the underlying mechanism of how the mutant PSEN gene may affect the function of the WT allele remains to be elucidated. Here we report that each of the loss-of-function γ-secretase variants that carries a PSEN1 mutation suppresses the protease activity of the WT γ-secretase on Aβ production. Each of these γ-secretase variants forms a stable oligomer with the WT γ-secretase in vitro in the presence of the detergent CHAPSO {3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonate}, but not digitonin. Importantly, robust protease activity of γ-secretase is detectable in the presence of CHAPSO, but not digitonin. These experimental observations suggest a dominant negative effect of the γ-secretase, in which the protease activity of WT γ-secretase is suppressed by the loss-of-function γ-secretase variants through hetero-oligomerization. The relevance of this finding to the genesis of Alzheimer's disease is critically evaluated.
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Affiliation(s)
- Rui Zhou
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China;
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Guanghui Yang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China;
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China;
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Institute of Biology, Westlake Institute for Advanced Study, Xihu District, Hangzhou 310064, Zhejiang Province, China
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16
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Li JM, Huang LL, Liu F, Tang BS, Yan XX. Can brain impermeable BACE1 inhibitors serve as anti-CAA medicine? BMC Neurol 2017; 17:163. [PMID: 28841840 PMCID: PMC5574137 DOI: 10.1186/s12883-017-0942-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 08/14/2017] [Indexed: 12/21/2022] Open
Abstract
Background Cerebral amyloid angiopathy (CAA) is characterized by the deposition of ß-amyloid peptides (Aß) in and surrounding the wall of microvasculature in the central nervous system, together with parenchymal amyloid plaques collectively referred to as cerebral amyloidosis, which occurs in the brain commonly among the elderly and more frequently in patients with Alzheimer’s disease (AD). CAA is associated with vascular injury and may cause devastating neurological outcomes. No therapeutic approach is available for this lesion to date. Main body ß-Secretase 1 (BACE1) is the enzyme initiating Aß production. Brain permeable BACE1 inhibitors targeting primarily at the parenchymal plaque pathology are currently evaluated in clinical trials. This article presents findings in support of a role of BACE1 elevation in the development of CAA, in addition to plaque pathogenesis. The rationale, feasibility, benefit and strategic issues for developing BACE1 inhibitors against CAA are discussed. Brain impermeable compounds are considered preferable as they might exhibit sufficient anti-CAA efficacy without causing significant neuronal/synaptic side effects. Conclusion Early pharmacological intervention to the pathogenesis of CAA is expected to provide significant protection for cerebral vascular health and hence brain health. Brain impermeable BACE1 inhibitors should be optimized and tested as potential anti-CAA therapeutics.
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Affiliation(s)
- Jian-Ming Li
- Department of Neurology & Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.,Neuroscience Research Center, Changsha Medical University, Changsha, Hunan, 410219, China
| | - Li-Ling Huang
- Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China
| | - Fei Liu
- Department of Neurosurgery, The Third Xiangya Hospital, Central South University, Changsha, Hunan, 410013, China
| | - Bei-Sha Tang
- Department of Neurology & Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Xiao-Xin Yan
- Department of Neurology & Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China. .,Department of Anatomy and Neurobiology, Central South University School of Basic Medical Science, Changsha, Hunan, 410013, China.
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17
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Szybińska A, Leśniak W. P53 Dysfunction in Neurodegenerative Diseases - The Cause or Effect of Pathological Changes? Aging Dis 2017; 8:506-518. [PMID: 28840063 PMCID: PMC5524811 DOI: 10.14336/ad.2016.1120] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 11/20/2016] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative diseases are a heterogeneous, mostly age-associated group of disorders characterized by progressive neuronal loss, the most prevalent being Alzheimer disease. It is anticipated that, with continuously increasing life expectancy, these diseases will pose a serious social and health problem in the near feature. Meanwhile, however, their etiology remains largely obscure even though all possible novel clues are being thoroughly examined. In this regard, a concept has been proposed that p53, as a transcription factor controlling many vital cellular pathways including apoptosis, may contribute to neuronal death common to all neurodegenerative disorders. In this work, we review the research devoted to the possible role of p53 in the pathogenesis of these diseases. We not only describe aberrant changes in p53 level/activity observed in CNS regions affected by particular diseases but, most importantly, put special attention to the complicated reciprocal regulatory ties existing between p53 and proteins commonly regarded as pathological hallmarks of these diseases, with the ultimate goal to identify the primary element of their pathogenesis.
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Affiliation(s)
- Aleksandra Szybińska
- 1Laboratory of Neurodegeneration, International Institute of Molecular and Cell Biology in Warsaw, 4 Ks. Trojdena St., 02-109 Warsaw, Poland.,2Department of Neurodegenerative Disorders, Laboratory of Neurogenetics, Mossakowski Medical Research Center Polish Academy of Sciences, 5 Pawinskiego St. 02-106 Warsaw, Poland
| | - Wiesława Leśniak
- 3Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology of the Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw Poland
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18
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Abstract
γ-secretase, a membrane-embedded aspartate protease, catalyzes peptide bond hydrolysis of a large variety of type I integral membrane proteins exemplified by amyloid precursor protein (APP). Cleavage of APP leads to formation of β-amyloid plaque, which is a hallmark of Alzheimer's disease (AD). Over 200 AD-associated mutations are mapped to presenilin 1 (PS1), the catalytic component of γ-secretase. In the past three years, several cryo-electron microscopy (cryo-EM) structures of human γ-secretase have been determined at near atomic resolutions. Here we summarize the methods involved and discuss structural features of γ-secretase and the associated functional insights.
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Affiliation(s)
- Guanghui Yang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Rui Zhou
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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19
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Jayne T, Newman M, Verdile G, Sutherland G, Münch G, Musgrave I, Moussavi Nik SH, Lardelli M. Evidence For and Against a Pathogenic Role of Reduced γ-Secretase Activity in Familial Alzheimer's Disease. J Alzheimers Dis 2017; 52:781-99. [PMID: 27060961 DOI: 10.3233/jad-151186] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The majority of mutations causing familial Alzheimer's disease (fAD) have been found in the gene PRESENILIN1 (PSEN1) with additional mutations in the related gene PRESENILIN2 (PSEN2). The best characterized function of PRESENILIN (PSEN) proteins is in γ-secretase enzyme activity. One substrate of γ-secretase is encoded by the gene AMYLOID BETA A4 PRECURSOR PROTEIN (AβPP/APP) that is a fAD mutation locus. AβPP is the source of the amyloid-β (Aβ) peptide enriched in the brains of people with fAD or the more common, late onset, sporadic form of AD, sAD. These observations have resulted in a focus on γ-secretase activity and Aβ as we attempt to understand the molecular basis of AD pathology. In this paper we briefly review some of the history of research on γ-secretase in AD. We then discuss the main ideas regarding the role of γ-secretase and the PSEN genes in this disease. We examine the significance of the "fAD mutation reading frame preservation rule" that applies to PSEN1 and PSEN2 (and AβPP) and look at alternative roles for AβPP and Aβ in fAD. We present a case for an alternative interpretation of published data on the role of γ-secretase activity and fAD-associated mutations in AD pathology. Evidence supports a "PSEN holoprotein multimer hypothesis" where PSEN fAD mutations generate mutant PSEN holoproteins that multimerize with wild type holoprotein and dominantly interfere with an AD-critical function(s) such as autophagy or secretion of Aβ. Holoprotein multimerization may be required for the endoproteolysis that activates PSENs' γ-secretase activity.
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Affiliation(s)
- Tanya Jayne
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide SA, Australia
| | - Morgan Newman
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide SA, Australia
| | - Giuseppe Verdile
- School of Biomedical Sciences, Curtin Health Innovation Research Institute - Biosciences, Faculty of Health Sciences, Curtin University, Kent Street, Bentley, WA, Australia.,School of Psychiatry and Clinical Neurosciences, University of Western Australia, Crawley, WA, Australia.,McCusker Alzheimer's Disease Research Foundation, Hollywood Private Hospital, Hollywood Medical Centre, Nedlands, WA, Australia
| | - Greg Sutherland
- Discipline of Pathology, Charles Perkins Centre, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Gerald Münch
- Molecular Medicine Research Group & School of Medicine, Western Sydney University, Campbelltown NSW, Australia
| | - Ian Musgrave
- Discipline of Pharmacology, School of Medicine, University of Adelaide, North Terrace, Adelaide, SA, Australia
| | - Seyyed Hani Moussavi Nik
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide SA, Australia
| | - Michael Lardelli
- Alzheimer's Disease Genetics Laboratory, Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, North Terrace, Adelaide SA, Australia
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20
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Dynamic Nature of presenilin1/γ-Secretase: Implication for Alzheimer's Disease Pathogenesis. Mol Neurobiol 2017; 55:2275-2284. [PMID: 28332150 DOI: 10.1007/s12035-017-0487-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 03/12/2017] [Indexed: 12/27/2022]
Abstract
Presenilin 1 (PS1) is a catalytic component of the γ-secretase complex, responsible for the intramembraneous cleavage of more than 90 type I transmembrane proteins, including Alzheimer's disease (AD)-related amyloid precursor protein (APP). The γ-secretase-mediated cleavage of the APP C-terminal membrane stub leads to the production of various amyloid β (Aβ) species. The assembly of Aβ into neurotoxic oligomers, which causes synaptic dysfunction and neurodegeneration, is influenced by the relative ratio of the longer (Aβ42/43) to shorter Aβ (Aβ40) peptides. The ratio of Aβ42 to Aβ40 depends on the conformation and activity of the PS1/γ-secretase enzymatic complex. The latter exists in a dynamic equilibrium of the so called "closed" and "open" conformational states, as determined by the Förster resonance energy transfer (FRET)-based PS1 conformation assay. Here we review several factors that can allosterically influence conformational status of the enzyme, and hence the production of Aβ peptides. These include genetic variations in PS1, APP and other γ-secretase components, environmental stressors implicated in AD pathogenesis and pharmacological agents. Since "closed" PS1 conformation is the common outcome of many AD-related insults, the novel assays monitoring PS1 conformation in live/intact cells in vivo and in vitro might be utilized for diagnostic purposes and for validation of the potential therapeutic approaches.
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21
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Hwang CJ, Park MH, Choi MK, Choi JS, Oh KW, Hwang DY, Han SB, Hong JT. Acceleration of amyloidogenesis and memory impairment by estrogen deficiency through NF-κB dependent beta-secretase activation in presenilin 2 mutant mice. Brain Behav Immun 2016; 53:113-122. [PMID: 26593275 DOI: 10.1016/j.bbi.2015.11.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 11/10/2015] [Accepted: 11/20/2015] [Indexed: 11/26/2022] Open
Abstract
Nearly 7-10 million people are living with Alzheimer's disease (AD) worldwide. Senile plaques composed of β-amyloid (Aβ) are a pathological hallmark of Alzheimer's disease. Presenilin 2 (PS2) mutations increase Aβ generation in the brains of AD patients. The Aβ is generated through the sequential cleavage of amyloid precursor protein by β- and γ-secretases. Additionally, increasing evidences suggest that estrogen can reduce the development of AD via regulation of β-secretases activity and beta-site APP-cleaving enzyme (BACE1) expression. But the underlying correlation mechanism of Aβ generation by PS2 mutations and estrogen remains to be clarified. To investigate the anti-amyloidogenesis effect of estrogen in a PS2 mutative condition, we examined memory impairment in ovariectomized PS2 mutation (N141I) mice in which cognitive function was assessed by the Morris water maze test and passive avoidance test. In addition, Western blot analysis, immunostaining, immunofluorescence staining, ELISA and enzyme activity assays were used to examine the degree of Aβ deposition in the brains. In the present study, Aβ accumulated more in the ovariectomized PS2 mutant mice brain, and greatly worsened memory impairment and glial activation as well as neurogenic inflammation. In parallel with increased memory impairment, activity of β-secretase and expression of the BACE1 increased inovariectomized PS2 mutant mice. Much higher activity of NF-κB was observed by EMSA in ovariectomized PS2 mutant mice. In addition, the Aβ level was decreased by treatment of β-estradiol through inhibiting BACE1 expression in PS2 transfacted PC12 cells. These results suggest that mutation of PS2 can lead to NF-κB mediate amyloidogensis, and this effect can be amplified by the absence of estrogen.
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Affiliation(s)
- Chul Ju Hwang
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 361-951, Republic of Korea
| | - Mi Hee Park
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 361-951, Republic of Korea
| | - Min Ki Choi
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 361-951, Republic of Korea
| | - Jung Soon Choi
- Osong Health Technology Administration Complex, 187 Osongsaengmyeong2(i)-ro, Osong-eup, Cheongwon-gun, Chungbuk 363-700, Republic of Korea
| | - Ki Wan Oh
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 361-951, Republic of Korea
| | - Dae Yeon Hwang
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 361-951, Republic of Korea
| | - Sang Bae Han
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 361-951, Republic of Korea
| | - Jin Tae Hong
- College of Pharmacy and Medical Research Center, Chungbuk National University, Osongsaengmyeong 1-ro 194-31, Osong-eup, Heungduk-gu, Cheongju, Chungbuk 361-951, Republic of Korea.
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22
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Brautigam H, Moreno CL, Steele JW, Bogush A, Dickstein DL, Kwok JBJ, Schofield PR, Thinakaran G, Mathews PM, Hof PR, Gandy S, Ehrlich ME. Physiologically generated presenilin 1 lacking exon 8 fails to rescue brain PS1-/- phenotype and forms complexes with wildtype PS1 and nicastrin. Sci Rep 2015; 5:17042. [PMID: 26608390 PMCID: PMC4660297 DOI: 10.1038/srep17042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/20/2015] [Indexed: 11/24/2022] Open
Abstract
The presenilin 1 (PSEN1) L271V mutation causes early-onset familial Alzheimer’s disease by disrupting the alternative splicing of the PSEN1 gene, producing some transcripts harboring the L271V point mutation and other transcripts lacking exon 8 (PS1∆exon8). We previously reported that PS1 L271V increased amyloid beta (Aβ) 42/40 ratios, while PS1∆exon8 reduced Aβ42/40 ratios, indicating that the former and not the exon 8 deletion transcript is amyloidogenic. Also, PS1∆exon8 did not rescue Aβ generation in PS1/2 double knockout cells indicating its identity as a severe loss-of-function splice form. PS1∆exon8 is generated physiologically raising the possibility that we had identified the first physiological inactive PS1 isoform. We studied PS1∆exon8in vivo by crossing PS1∆exon8 transgenics with either PS1-null or Dutch APPE693Q mice. As a control, we crossed APPE693Q with mice expressing a deletion in an adjacent exon (PS1∆exon9). PS1∆exon8 did not rescue embryonic lethality or Notch-deficient phenotypes of PS1-null mice displaying severe loss of function in vivo. We also demonstrate that this splice form can interact with wildtype PS1 using cultured cells and co-immunoprecipitation (co-IP)/bimolecular fluorescence complementation. Further co-IP demonstrates that PS1∆exon8 interacts with nicastrin, participating in the γ–secretase complex formation. These data support that catalytically inactive PS1∆exon8 is generated physiologically and participates in protein-protein interactions.
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Affiliation(s)
- Hannah Brautigam
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53706
| | - Cesar L Moreno
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - John W Steele
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Cellular and Molecular Medicine,University of California San Diego, La Jolla, CA 92037.,Department of Preclinical Biology, OrPhi Therapeutics, Carlsbad, CA 92008
| | - Alexey Bogush
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, PA 19104
| | - Dara L Dickstein
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - John B J Kwok
- Neuroscience Research Australia, Sydney, NSW 2031, Australia.,School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Peter R Schofield
- Neuroscience Research Australia, Sydney, NSW 2031, Australia.,School of Medical Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Gopal Thinakaran
- Departments of Neurobiology, Neurology, and Pathology, The University of Chicago, IL 60637
| | - Paul M Mathews
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016.,Nathan Kline Institute Center for Dementia Research, Orangeburg, NY 10962
| | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Sam Gandy
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,James J. Peters VA Medical Center, Bronx, NY 10468
| | - Michelle E Ehrlich
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
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23
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Adalbert R, Coleman MP. Review: Axon pathology in age-related neurodegenerative disorders. Neuropathol Appl Neurobiol 2015; 39:90-108. [PMID: 23046254 DOI: 10.1111/j.1365-2990.2012.01308.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2012] [Accepted: 09/24/2012] [Indexed: 12/12/2022]
Abstract
'Dying back' axon degeneration is a prominent feature of many age-related neurodegenerative disorders and is widespread in normal ageing. Although the mechanisms of disease- and age-related losses may differ, both contribute to symptoms. Here, we review recent advances in understanding axon pathology in age-related neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and glaucoma. In particular, we highlight the importance of axonal transport, autophagy, traumatic brain injury and mitochondrial quality control. We then place these disease mechanisms in the context of changes to axons and dendrites that occur during normal ageing. We discuss what makes ageing such an important risk factor for many neurodegenerative disorders and conclude that the processes of normal ageing and disease combine at the molecular, cellular or systems levels in a range of disorders to produce symptoms. Pathology identical to disease also occurs at the cellular level in most elderly individuals. Thus, normal ageing and age-related disease are inextricably linked and the term 'healthy ageing' downplays the important contributions of cellular pathology. For a full understanding of normal ageing or age-related disease we must study both processes.
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Affiliation(s)
- R Adalbert
- Signalling Programme, The Babraham Institute, Babraham, Cambridge, UK
| | - M P Coleman
- Signalling Programme, The Babraham Institute, Babraham, Cambridge, UK
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24
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De Strooper B, Chávez Gutiérrez L. Learning by Failing: Ideas and Concepts to Tackle γ-Secretases in Alzheimer's Disease and Beyond. Annu Rev Pharmacol Toxicol 2015; 55:419-37. [DOI: 10.1146/annurev-pharmtox-010814-124309] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Bart De Strooper
- VIB Center for the Biology of Disease, Vlaams Instituut voor Biotechnologie, BE-3000 Leuven, Belgium
- Center for Human Genetics, Laboratory for the Research of Neurodegenerative Diseases, KU Leuven, BE-3000 Leuven, Belgium; ,
| | - Lucía Chávez Gutiérrez
- VIB Center for the Biology of Disease, Vlaams Instituut voor Biotechnologie, BE-3000 Leuven, Belgium
- Center for Human Genetics, Laboratory for the Research of Neurodegenerative Diseases, KU Leuven, BE-3000 Leuven, Belgium; ,
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25
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High resolution imaging study of interactions between the 37 kDa/67 kDa laminin receptor and APP, beta-secretase and gamma-secretase in Alzheimer's disease. PLoS One 2014; 9:e100373. [PMID: 24972054 PMCID: PMC4074076 DOI: 10.1371/journal.pone.0100373] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 05/27/2014] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia affecting the elderly. Neurodegeneration is caused by the amyloid beta (Aβ) peptide which is generated from the sequential proteolytic cleavage of the Amyloid Precursor Protein (APP) by the β– and γ- secretases. Previous reports revealed that the 37 kDa/67 kDa laminin receptor (LRP/LR) is involved in APP processing, however, the exact mechanism by which this occurs remains largely unclear. This study sought to assess whether LRP/LR interacted with APP, β- or γ-secretase. Detailed confocal microscopy revealed that LRP/LR showed a strong co-localisation with APP, β- and γ-secretase, respectively, at various sub-cellular locations. Superresolution Structured Illumination Microscopy (SR-SIM) showed that interactions were unlikely between LRP/LR and APP and β-secretase, respectively, while there was strong co-localisation between LRP/LR and γ-secretase at this 80 nm resolution. FRET was further employed to assess the possibility of protein-protein interactions and only an interaction between LRP/LR and γ-secretase was found. FLAG co-immunoprecipitation confirmed these findings as LRP/LR co-immunoprecipitated with γ-secretase, but failed to do so with APP. These findings indicate that LRP/LR exerts its influence on Aβ shedding via a direct interaction with the γ-secretase and possibly an indirect interaction with the β-secretase.
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26
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Cruchaga C, Karch CM, Jin SC, Benitez BA, Cai Y, Guerreiro R, Harari O, Norton J, Budde J, Bertelsen S, Jeng AT, Cooper B, Skorupa T, Carrell D, Levitch D, Hsu S, Choi J, Ryten M, Sassi C, Bras J, Gibbs RJ, Hernandez DG, Lupton MK, Powell J, Forabosco P, Ridge PG, Corcoran CD, Tschanz JT, Norton MC, Munger RG, Schmutz C, Leary M, Demirci FY, Bamne MN, Wang X, Lopez OL, Ganguli M, Medway C, Turton J, Lord J, Braae A, Barber I, Brown K, Pastor P, Lorenzo-Betancor O, Brkanac Z, Scott E, Topol E, Morgan K, Rogaeva E, Singleton A, Hardy J, Kamboh MI, George-Hyslop PS, Cairns N, Morris JC, Kauwe JS, Goate AM. Rare coding variants in the phospholipase D3 gene confer risk for Alzheimer's disease. Nature 2014; 505:550-554. [PMID: 24336208 PMCID: PMC4050701 DOI: 10.1038/nature12825] [Citation(s) in RCA: 339] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/31/2013] [Indexed: 01/18/2023]
Abstract
Genome-wide association studies (GWAS) have identified several risk variants for late-onset Alzheimer's disease (LOAD). These common variants have replicable but small effects on LOAD risk and generally do not have obvious functional effects. Low-frequency coding variants, not detected by GWAS, are predicted to include functional variants with larger effects on risk. To identify low-frequency coding variants with large effects on LOAD risk, we carried out whole-exome sequencing (WES) in 14 large LOAD families and follow-up analyses of the candidate variants in several large LOAD case-control data sets. A rare variant in PLD3 (phospholipase D3; Val232Met) segregated with disease status in two independent families and doubled risk for Alzheimer's disease in seven independent case-control series with a total of more than 11,000 cases and controls of European descent. Gene-based burden analyses in 4,387 cases and controls of European descent and 302 African American cases and controls, with complete sequence data for PLD3, reveal that several variants in this gene increase risk for Alzheimer's disease in both populations. PLD3 is highly expressed in brain regions that are vulnerable to Alzheimer's disease pathology, including hippocampus and cortex, and is expressed at significantly lower levels in neurons from Alzheimer's disease brains compared to control brains. Overexpression of PLD3 leads to a significant decrease in intracellular amyloid-β precursor protein (APP) and extracellular Aβ42 and Aβ40 (the 42- and 40-residue isoforms of the amyloid-β peptide), and knockdown of PLD3 leads to a significant increase in extracellular Aβ42 and Aβ40. Together, our genetic and functional data indicate that carriers of PLD3 coding variants have a twofold increased risk for LOAD and that PLD3 influences APP processing. This study provides an example of how densely affected families may help to identify rare variants with large effects on risk for disease or other complex traits.
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Affiliation(s)
- Carlos Cruchaga
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
- Hope Center Program on Protein Aggregation and
Neurodegeneration, Washington University St. Louis, MO, USA
| | - Celeste M. Karch
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
- Hope Center Program on Protein Aggregation and
Neurodegeneration, Washington University St. Louis, MO, USA
| | - Sheng Chih Jin
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Bruno A. Benitez
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Yefei Cai
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Rita Guerreiro
- Department of Molecular Neuroscience, UCL Institute of
Neurology, London WC1N 3BG, UK
- Laboratory of Neurogenetics, National Institute on Aging,
National Institutes of Health, Bethesda, Maryland, United States of America
| | - Oscar Harari
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Joanne Norton
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - John Budde
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Sarah Bertelsen
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Amanda T. Jeng
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Breanna Cooper
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Tara Skorupa
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - David Carrell
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Denise Levitch
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Simon Hsu
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Jiyoon Choi
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
| | - Mina Ryten
- Department of Molecular Neuroscience, UCL Institute of
Neurology, London WC1N 3BG, UK
- on behalf of UKBEC (UK Brain Expression Consortium)
| | - Celeste Sassi
- Department of Molecular Neuroscience, UCL Institute of
Neurology, London WC1N 3BG, UK
- Laboratory of Neurogenetics, National Institute on Aging,
National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jose Bras
- Department of Molecular Neuroscience, UCL Institute of
Neurology, London WC1N 3BG, UK
| | - Raphael J. Gibbs
- Department of Molecular Neuroscience, UCL Institute of
Neurology, London WC1N 3BG, UK
- Laboratory of Neurogenetics, National Institute on Aging,
National Institutes of Health, Bethesda, Maryland, United States of America
| | - Dena G. Hernandez
- Department of Molecular Neuroscience, UCL Institute of
Neurology, London WC1N 3BG, UK
- Laboratory of Neurogenetics, National Institute on Aging,
National Institutes of Health, Bethesda, Maryland, United States of America
| | - Michelle K. Lupton
- Institute of Psychiatry, King's College London, London,
UK
- Neuroimaging Genetics, QIMR Berghofer Medical Research
Institute, Brisbane, Australia
| | - John Powell
- Institute of Psychiatry, King's College London, London,
UK
| | - Paola Forabosco
- Istituto di Genetica delle Popolazioni – CNR,
Sassari, Italy
| | - Perry G. Ridge
- Department of Biology, Brigham Young University, Provo,
UT, 84602
| | - Christopher D. Corcoran
- Department of Mathematics and Statistics, Utah State
University, Logan, UT
- Center for Epidemiologic Studies, Utah State University,
Logan, UT
| | - JoAnn T. Tschanz
- Center for Epidemiologic Studies, Utah State University,
Logan, UT
- Department of Psychology, Utah State University, Logan,
UT
| | - Maria C. Norton
- Center for Epidemiologic Studies, Utah State University,
Logan, UT
- Department of Psychology, Utah State University, Logan,
UT
- Department of Family Consumer and Human Development,
Utah State University, Logan, UT
| | - Ronald G. Munger
- Department of Family Consumer and Human Development,
Utah State University, Logan, UT
- Department of Nutrition, Dietetics, and Food Sciences,
Utah State University, Logan, UT
| | - Cameron Schmutz
- Department of Biology, Brigham Young University, Provo,
UT, 84602
| | - Maegan Leary
- Department of Biology, Brigham Young University, Provo,
UT, 84602
| | - F. Yesim Demirci
- Department of Human Genetics, University of Pittsburgh,
Pittsburgh, PA
| | - Mikhil N. Bamne
- Department of Human Genetics, University of Pittsburgh,
Pittsburgh, PA
| | - Xingbin Wang
- Department of Human Genetics, University of Pittsburgh,
Pittsburgh, PA
| | - Oscar L. Lopez
- Alzheimer's Disease Research Center, University of
Pittsburgh, Pittsburgh, PA
- Department of Neurology, University of Pittsburgh,
Pittsburgh, PA
| | - Mary Ganguli
- Department of Psychiatry, University of Pittsburgh,
Pittsburgh, PA
| | - Christopher Medway
- Human Genetics, School of Molecular Medical Sciences,
University of Nottingham, Nottingham, NG7 2UH, UK
| | - James Turton
- Human Genetics, School of Molecular Medical Sciences,
University of Nottingham, Nottingham, NG7 2UH, UK
| | - Jenny Lord
- Human Genetics, School of Molecular Medical Sciences,
University of Nottingham, Nottingham, NG7 2UH, UK
| | - Anne Braae
- Human Genetics, School of Molecular Medical Sciences,
University of Nottingham, Nottingham, NG7 2UH, UK
| | - Imelda Barber
- Human Genetics, School of Molecular Medical Sciences,
University of Nottingham, Nottingham, NG7 2UH, UK
| | - Kristelle Brown
- Human Genetics, School of Molecular Medical Sciences,
University of Nottingham, Nottingham, NG7 2UH, UK
| | | | - Pau Pastor
- Neurogenetics Laboratory, Division of Neurosciences,
Center for Applied Medical Research, University of Navarra, Pamplona, Spain
- Department of Neurology, Clínica Universidad de
Navarra, School of Medicine, University of Navarra, Pamplona, Spain
- CIBERNED, Centro de Investigación
Biomédica en Red de Enfermedades Neurodegenerativas, Instituto de Salud
Carlos III, Spain
| | - Oswaldo Lorenzo-Betancor
- Neurogenetics Laboratory, Division of Neurosciences,
Center for Applied Medical Research, University of Navarra, Pamplona, Spain
| | | | - Erick Scott
- The Scripps Research Institute, La Jolla, CA, US
| | - Eric Topol
- The Scripps Research Institute, La Jolla, CA, US
| | - Kevin Morgan
- Human Genetics, School of Molecular Medical Sciences,
University of Nottingham, Nottingham, NG7 2UH, UK
| | - Ekaterina Rogaeva
- Tanz Centre for Research in Neurodegenerative Diseases,
University of Toronto
| | - Andy Singleton
- Laboratory of Neurogenetics, National Institute on Aging,
National Institutes of Health, Bethesda, Maryland, United States of America
| | - John Hardy
- Department of Molecular Neuroscience, UCL Institute of
Neurology, London WC1N 3BG, UK
| | - M. Ilyas Kamboh
- Alzheimer's Disease Research Center, University of
Pittsburgh, Pittsburgh, PA
- Department of Psychiatry, University of Pittsburgh,
Pittsburgh, PA
| | - Peter St George-Hyslop
- Tanz Centre for Research in Neurodegenerative Diseases,
University of Toronto
- Cambridge Institute for Medical Research, and the
Department of Clinical Neurosciences, University of Cambridge
| | - Nigel Cairns
- Hope Center Program on Protein Aggregation and
Neurodegeneration, Washington University St. Louis, MO, USA
- Pathology and Immunology, Washington University, St.
Louis, MO, USA
| | - John C. Morris
- Pathology and Immunology, Washington University, St.
Louis, MO, USA
- Department of Neurology, Washington University, St. Louis,
MO, USA
- Knight ADRC, Washington University, St. Louis, MO,
USA
| | - John S.K. Kauwe
- Department of Biology, Brigham Young University, Provo,
UT, 84602
| | - Alison M. Goate
- Department of Psychiatry, Washington University, St.
Louis, MO, USA
- Hope Center Program on Protein Aggregation and
Neurodegeneration, Washington University St. Louis, MO, USA
- Department of Neurology, Washington University, St. Louis,
MO, USA
- Knight ADRC, Washington University, St. Louis, MO,
USA
- Department of Genetics, Washington University, St. Louis,
MO, USA
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27
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Wolfe MS. Toward the structure of presenilin/γ-secretase and presenilin homologs. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1828:2886-97. [PMID: 24099007 PMCID: PMC3801419 DOI: 10.1016/j.bbamem.2013.04.015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/03/2013] [Accepted: 04/11/2013] [Indexed: 01/30/2023]
Abstract
Presenilin is the catalytic component of the γ-secretase complex, a membrane-embedded aspartyl protease that plays a central role in biology and in the pathogenesis of Alzheimer's disease. Upon assembly with its three protein cofactors (nicastrin, Aph-1 and Pen-2), presenilin undergoes autoproteolysis into two subunits, each of which contributes one of the catalytic aspartates to the active site. A family of presenilin homologs, including signal peptide peptidase, possess proteolytic activity without the need for other protein factors, and these simpler intramembrane aspartyl proteases have given insight into the action of presenilin within the γ-secretase complex. Cellular and molecular studies support a nine-transmembrane topology for presenilins and their homologs, and small-molecule inhibitors and cysteine scanning with crosslinking have suggested certain presenilin residues and regions that contribute to substrate recognition and handling. Identification of partial complexes has also offered clues to protein-protein interactions within the γ-secretase complex. Biophysical methods have allowed 3D views of the γ-secretase complex and presenilins. Most recently, the crystal structure of a microbial presenilin homolog has confirmed a nine-transmembrane topology and intramembranous location and proximity of the two conserved and essential aspartates. The crystal structure also provides a platform for the formulation of specific hypotheses regarding substrate interaction and catalysis as well as the pathogenic mechanism of Alzheimer-causing presenilin mutations. This article is part of a Special Issue entitled: Intramembrane Proteases.
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Affiliation(s)
- Michael S Wolfe
- Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, H.I.M. 754, Boston, MA 02115 USA.
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28
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Trafficking in neurons: Searching for new targets for Alzheimer's disease future therapies. Eur J Pharmacol 2013; 719:84-106. [DOI: 10.1016/j.ejphar.2013.07.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/11/2013] [Indexed: 11/22/2022]
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29
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Tagami S, Okochi M, Yanagida K, Kodama T, Arai T, Kuwano R, Ikeuchi T, Takeda M. Relative ratio and level of amyloid-β 42 surrogate in cerebrospinal fluid of familial Alzheimer disease patients with presenilin 1 mutations. NEURODEGENER DIS 2013; 13:166-70. [PMID: 24192669 DOI: 10.1159/000355258] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/23/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Presenilin 1 (PS1) mutations associated with familial Alzheimer disease (FAD) generally increase the amyloid-β 42 (Aβ42) to Aβ40 ratio secreted in cultured cells. Some of these mutants reduce the secretion of Aβ40 rather than increase that of Aβ42. Since it has been difficult to estimate Aβ42 secretion in brains of PS1-FAD patients due to substantial Aβ42 accumulation, it remains unknown whether the enhanced Aβ42 to Aβ40 ratio in brains of FAD patients is caused by elevated Aβ42 secretion or by reduced secretion of Aβ40. OBJECTIVE/METHODS Cerebrospinal fluids (CSF) of PS1-FAD patients and neurological control patients (controls) were collected. Levels of CSF amyloid precursor-like protein-1-derived Aβ-like peptide (APL1β), including APL1β28, an Aβ42 surrogate marker, were quantified by liquid chromatography tandem mass spectrometry, and Aβ42 secretion in the brain was estimated. RESULTS The relative ratio of CSF APL1β28 to total APL1β was higher in PS1-FAD patients than in controls. Importantly, CSF APL1β28 was not significantly higher. However, C-terminally shorter CSF APL1β25 and APL1β27 were significantly lower in PS1-FAD patients and, as expected, so were CSF Aβ40 and Aβ42. CONCLUSION A higher relative ratio of the CSF Aβ42 surrogate in PS1-FAD patients is not due to its increase in CSF, suggesting that massive Aβ42 accumulation in the PS1-FAD brain occurs without an apparent increase in Aβ42 secretion.
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Affiliation(s)
- Shinji Tagami
- Neuropsychiatry and Neurochemistry, Division of Internal Medicine, Department of Integrated Medicine, Osaka University Graduate School of Medicine, Suita, Japan
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30
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Robakis NK, Georgakopoulos A. Allelic interference: a mechanism for trans-dominant transmission of loss of function in the neurodegeneration of familial Alzheimer's disease. NEURODEGENER DIS 2013; 13:126-30. [PMID: 24081144 DOI: 10.1159/000354241] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 07/08/2013] [Indexed: 11/19/2022] Open
Abstract
Presenilins (PSs) are catalytic components of the γ-secretase complexes that promote the ε-cleavage of cell surface proteins producing cytosolic peptides shown to function in cell signaling and gene expression. In addition, secretase cleavages at γ-sites of amyloid precursor protein substrates produce the amyloid-β (Aβ) peptides found in all people. Aggregation of Aβ peptides form the amyloid fibrils found in amyloid plaques of Alzheimer's disease (AD) patients and aged individuals. A common hypothesis suggests that AD is caused by aggregated Aβ peptides, but treatments with either inhibitors of Aβ production or anti-Aβ antibodies showed no therapeutic value. Importantly, recent evidence [Marambaud et al.: Cell 2003;114:635-645] shows that PS familial AD (FAD) mutations cause a loss of γ-secretase cleavage function at the ε-site of substrates manifested by a decreased production of cytosolic peptides and an accumulation of transmembrane γ-secretase substrates. These data support the hypothesis that PS FAD mutations promote neurotoxicity by inhibiting the γ-secretase-catalyzed ε-cleavage of substrates, thus reducing cell signaling while causing accumulation of membrane-bound cytotoxic peptides. Similar mechanisms may be involved in toxicities observed in clinical trials of γ-secretase inhibitors. A model of allelic interference may explain the dominant negative transmission of neurotoxic loss of function in FAD neurodegeneration.
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Affiliation(s)
- Nikolaos K Robakis
- Departments of Psychiatry and Neuroscience, Center for Molecular Biology and Genetics of Neurodegeneration, Ican School of Medicine at Mount Sinai Medical Center, New York University, New York, N.Y., USA
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31
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Trans-dominant negative effects of pathogenic PSEN1 mutations on γ-secretase activity and Aβ production. J Neurosci 2013; 33:11606-17. [PMID: 23843529 DOI: 10.1523/jneurosci.0954-13.2013] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Mutations in the PSEN1 gene encoding Presenilin-1 (PS1) are the predominant cause of familial Alzheimer's disease (FAD), but the underlying mechanisms remain unresolved. To reconcile the dominant action of pathogenic PSEN1 mutations with evidence that they confer a loss of mutant protein function, we tested the hypothesis that PSEN1 mutations interfere with γ-secretase activity in a dominant-negative manner. Here, we show that pathogenic PSEN1 mutations act in cis to impair mutant PS1 function and act in trans to inhibit wild-type PS1 function. Coexpression of mutant and wild-type PS1 at equal gene dosage in presenilin-deficient mouse embryo fibroblasts resulted in trans-dominant-negative inhibition of wild-type PS1 activity, suppressing γ-secretase-dependent cleavage of APP and Notch. Surprisingly, mutant PS1 could stimulate production of Aβ42 by wild-type PS1 while decreasing its production of Aβ40. Mutant and wild-type PS1 efficiently coimmunoprecipitated, suggesting that mutant PS1 interferes with wild-type PS1 activity via physical interaction. These results support the conclusion that mutant PS1 causes wild-type PS1 to adopt an altered conformation with impaired catalytic activity and substrate specificity. Our findings reveal a novel mechanism of action for pathogenic PSEN1 mutations and suggest that dominant-negative inhibition of presenilin activity plays an important role in FAD pathogenesis.
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32
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Song Y, Hustedt EJ, Brandon S, Sanders CR. Competition between homodimerization and cholesterol binding to the C99 domain of the amyloid precursor protein. Biochemistry 2013; 52:5051-64. [PMID: 23865807 DOI: 10.1021/bi400735x] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The 99-residue transmembrane C-terminal domain (C99, also known as β-CTF) of the amyloid precursor protein (APP) is the product of the β-secretase cleavage of the full-length APP and is the substrate for γ-secretase cleavage. The latter cleavage releases the amyloid-β polypeptides that are closely associated with Alzheimer's disease. C99 is thought to form homodimers; however, the free energy in favor of dimerization has not previously been quantitated. It was also recently documented that cholesterol forms a 1:1 complex with monomeric C99 in bicelles. Here, the affinities for both homodimerization and cholesterol binding to C99 were measured in bilayered lipid vesicles using both electron paramagnetic resonance (EPR) and Förster resonance energy transfer (FRET) methods. Homodimerization and cholesterol binding were seen to be competitive processes that center on the transmembrane G₇₀₀XXXG₇₀₄XXXG₇₀₈ glycine-zipper motif and adjacent Gly709. On one hand, the observed Kd for cholesterol binding (Kd = 2.7 ± 0.3 mol %) is on the low end of the physiological cholesterol concentration range in mammalian cell membranes. On the other hand, the observed K(d) for homodimerization (K(d) = 0.47 ± 0.15 mol %) likely exceeds the physiological concentration range for C99. These results suggest that the 1:1 cholesterol/C99 complex will be more highly populated than C99 homodimers under most physiological conditions. These observations are of relevance for understanding the γ-secretase cleavage of C99.
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Affiliation(s)
- Yuanli Song
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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33
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De Strooper B, Iwatsubo T, Wolfe MS. Presenilins and γ-secretase: structure, function, and role in Alzheimer Disease. Cold Spring Harb Perspect Med 2013; 2:a006304. [PMID: 22315713 DOI: 10.1101/cshperspect.a006304] [Citation(s) in RCA: 308] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Presenilins were first discovered as sites of missense mutations responsible for early-onset Alzheimer disease (AD). The encoded multipass membrane proteins were subsequently found to be the catalytic components of γ-secretases, membrane-embedded aspartyl protease complexes responsible for generating the carboxyl terminus of the amyloid β-protein (Aβ) from the amyloid protein precursor (APP). The protease complex also cleaves a variety of other type I integral membrane proteins, most notably the Notch receptor, signaling from which is involved in many cell differentiation events. Although γ-secretase is a top target for developing disease-modifying AD therapeutics, interference with Notch signaling should be avoided. Compounds that alter Aβ production by γ-secretase without affecting Notch proteolysis and signaling have been identified and are currently at various stages in the drug development pipeline.
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Affiliation(s)
- Bart De Strooper
- Center for Human Genetics, Leuven Institute for Neurodegenerative Diseases, KULeuven, 3000 Leuven, Belgium; Department of Molecular and Developmental Genetics, VIB, 3000, Leuven, Belgium
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Pinnix I, Ghiso JA, Pappolla MA, Sambamurti K. Major carboxyl terminal fragments generated by γ-secretase processing of the Alzheimer amyloid precursor are 50 and 51 amino acids long. Am J Geriatr Psychiatry 2013; 21:474-83. [PMID: 23570890 PMCID: PMC3740189 DOI: 10.1016/j.jagp.2013.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 02/04/2013] [Accepted: 02/15/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To understand the cleavage of the amyloid β protein (Aβ) precursor (APP) by γ-secretase and to determine its changes in a representative familial Alzheimer disease (FAD) mutation. METHODS Transfected cells expressing wild-type and FAD mutant APP were analyzed for changes in the levels of the major secreted Aβ species and of the corresponding intracellular C-terminal APP fragments (APP intracellular domain, AICD) generated by γ-secretase, whereas radio-sequencing was used to precisely identify the resulting cleavage site(s). RESULTS The AICD fragment(s) generated by γ-secretase cleavage comigrated in gels with a 50-residue synthetic peptide used as control, which is smaller than the 59 and 57 residues predicted from Aβ ending at positions 40 (Aβ40) and 42 (Aβ42), respectively. In agreement with previous findings, an FAD mutant form of presenilin 1 (PS1-M139V) significantly increased the longer Aβ42 while showing trends toward reducing Aβ40. AICD levels were reduced by the mutation, suggesting that γ-secretase activity may be actually impaired by the mutation. Radiosequence analysis in cells expressing wild-type PS1 detected γ-secretase cleavage sites at the Aβ peptide bond L(49)-V(50) to generate a 50-amino acid (aa) AICD fragment (AICD50) and the Aβ peptide bond T(48)-L(49), generating an AICD of 51 aa (AICD51). No other cleavage sites were reliably detected. CONCLUSIONS Based on findings that the FAD mutation that increases Aβ42 also reduces AICD, we propose that γ-secretase activity is impaired by FAD mutations and predict that physiologic and environmental agents that inhibit γ-secretase will actually induce AD pathogenesis rather that prevent it. Furthermore, we propose that the cleavage site to generate AICD is naturally ragged and occurs predominantly at two sites 48 and 49 aa from the start of the Aβ sequence. Thus, end specific antibodies to these two sites will need to be generated to study the quantitative relationships between these two cleavages in sporadic AD and FAD.
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Affiliation(s)
| | | | | | - Kumar Sambamurti
- To whom correspondence should be addressed: Kumar Sambamurti, Ph.D., Professor of Neuroscience, 173 Ashley Avenue, BSB 403, Charleston, SC 29425, Tel: 843 792 4315,
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35
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So PP, Khodr CE, Chen CD, Abraham CR. Comparable dimerization found in wildtype and familial Alzheimer's disease amyloid precursor protein mutants. AMERICAN JOURNAL OF NEURODEGENERATIVE DISEASE 2013; 2:15-28. [PMID: 23515184 PMCID: PMC3601467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 02/06/2013] [Indexed: 06/01/2023]
Abstract
Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disorder marked by memory impairment and cognitive deficits. A major component of AD pathology is the accumulation of amyloid plaques in the brain, which are comprised of amyloid beta (Aβ) peptides derived from the amyloidogenic processing of the amyloid precursor protein (AβPP) by β- and γ-secretases. In a subset of patients, inheritance of mutations in the AβPP gene is responsible for altering Aβ production, leading to early onset disease. Interestingly, many of these familial mutations lie within the transmembrane domain of the protein near the GxxxG and GxxxA dimerization motifs that are important for transmembrane interactions. As AβPP dimerization has been linked to changes in Aβ production, it is of interest to know whether familial AβPP mutations affect full-length APP dimerization. Using bimolecular fluorescence complementation (BiFC), blue native gel electrophoresis, and live cell chemical cross-linking, we found that familial Alzheimer's disease (FAD) mutations do not affect full-length AβPP dimerization in transfected HEK293 and COS7 cells. It follows that changes in AβPP dimerization are not necessary for altered Aβ production, and in FAD mutations, changes in Aβ levels are more likely a result of alternative proteolytic processing.
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Affiliation(s)
- Pauline Pl So
- Department of Medicine Graduate Program in Molecular Medicine, Boston University School of Medicine 72 East Concord Street, K-304, Boston, MA, 02118, USA
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36
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Robakis NK. Cell signaling abnormalities may drive neurodegeneration in familial Alzheimer disease. Neurochem Res 2013; 39:570-5. [PMID: 23436150 DOI: 10.1007/s11064-013-1003-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 02/04/2013] [Accepted: 02/11/2013] [Indexed: 11/28/2022]
Abstract
Presenilins (PSs) are catalytic components of the γ-secretase complex that produces Aβ peptides. Substrates of γ-secretase are membrane-bound protein fragments deriving from the cleavage of extracellular sequence of cell surface proteins. APP-derived γ-secretase substrates are cleaved at gamma (γ) sites to produce Aβ while cleavage at the epsilon (ε) site produces AICD proposed to function in transcription. In addition to APP, γ-secretase promotes the ε-cleavage of a large number of cell surface proteins producing cytosolic peptides shown to function in cell signaling. A common hypothesis suggests that Alzheimer's disease (AD) is caused by Aβ peptides or their products. Treatment of patients with inhibitors of Aβ production however, showed no therapeutic benefits while inducing cytotoxicity. Similarly, treatments with anti-Aβ antibodies yielded disappointing results. Importantly, recent evidence shows that PS familial AD (FAD) mutations cause a loss of γ-secretase cleavage activity at ε site of substrates thus inhibiting production of biologically important cell signaling peptides while promoting accumulation of membrane-bound cytotoxic substrates. These data support a hypothesis that FAD mutations may increase neurotoxicity by inhibiting the γ-secretase-catalyzed ε cleavage of substrates thus interfering with cell signaling while also promoting accumulation of cytotoxic peptides. Similar mechanisms may explain γ-secretase inhibitor-associated toxicities observed in clinical trials. Here we discuss evidence that FAD neurodegeneration may be caused by loss of γ-secretase cleavage function at ε sites of substrates.
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Affiliation(s)
- Nikolaos K Robakis
- Departments of Psychiatry and Neuroscience, Mount Sinai School of Medicine, New York University, One Gustave Levy Pl., Box 1229, New York, NY, 10029, USA,
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37
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Structure of a presenilin family intramembrane aspartate protease. Nature 2012; 493:56-61. [PMID: 23254940 DOI: 10.1038/nature11801] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Accepted: 11/16/2012] [Indexed: 12/22/2022]
Abstract
Presenilin and signal peptide peptidase (SPP) are intramembrane aspartyl proteases that regulate important biological functions in eukaryotes. Mechanistic understanding of presenilin and SPP has been hampered by lack of relevant structural information. Here we report the crystal structure of a presenilin/SPP homologue (PSH) from the archaeon Methanoculleus marisnigri JR1. The protease, comprising nine transmembrane segments (TMs), adopts a previously unreported protein fold. The amino-terminal domain, consisting of TM1-6, forms a horseshoe-shaped structure, surrounding TM7-9 of the carboxy-terminal domain. The two catalytic aspartate residues are located on the cytoplasmic side of TM6 and TM7, spatially close to each other and approximately 8 Å into the lipid membrane surface. Water molecules gain constant access to the catalytic aspartates through a large cavity between the amino- and carboxy-terminal domains. Structural analysis reveals insights into the presenilin/SPP family of intramembrane proteases.
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38
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Sykes AM, Palstra N, Abankwa D, Hill JM, Skeldal S, Matusica D, Venkatraman P, Hancock JF, Coulson EJ. The effects of transmembrane sequence and dimerization on cleavage of the p75 neurotrophin receptor by γ-secretase. J Biol Chem 2012; 287:43810-24. [PMID: 23105112 DOI: 10.1074/jbc.m112.382903] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cleavage of transmembrane receptors by γ-secretase is the final step in the process of regulated intramembrane proteolysis (RIP) and has a significant impact on receptor function. Although relatively little is known about the molecular mechanism of γ-secretase enzymatic activity, it is becoming clear that substrate dimerization and/or the α-helical structure of the substrate can regulate the site and rate of γ-secretase activity. Here we show that the transmembrane domain of the pan-neurotrophin receptor p75(NTR), best known for regulating neuronal death, is sufficient for its homodimerization. Although the p75(NTR) ligands NGF and pro-NGF do not induce homerdimerization or RIP, homodimers of p75(NTR) are γ-secretase substrates. However, dimerization is not a requirement for p75(NTR) cleavage, suggesting that γ-secretase has the ability to recognize and cleave each receptor molecule independently. The transmembrane cysteine 257, which mediates covalent p75(NTR) interactions, is not crucial for homodimerization, but this residue is required for normal rates of γ-secretase cleavage. Similarly, mutation of the residues alanine 262 and glycine 266 of an AXXXG dimerization motif flanking the γ-secretase cleavage site within the p75(NTR) transmembrane domain alters the orientation of the domain and inhibits γ-secretase cleavage of p75(NTR). Nonetheless, heteromer interactions of p75(NTR) with TrkA increase full-length p75(NTR) homodimerization, which in turn potentiates the rate of γ-cleavage following TrkA activation independently of rates of α-cleavage. These results provide support for the idea that the helical structure of the p75(NTR) transmembrane domain, which may be affected by co-receptor interactions, is a key element in γ-secretase-catalyzed cleavage.
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Affiliation(s)
- Alex M Sykes
- Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia
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39
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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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40
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Mapping Molecular Memory: Navigating the Cellular Pathways of Learning. Cell Mol Neurobiol 2012; 32:919-41. [DOI: 10.1007/s10571-012-9836-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 03/21/2012] [Indexed: 01/25/2023]
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41
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Afshar Y, Jeong JW, Roqueiro D, DeMayo F, Lydon J, Radtke F, Radnor R, Miele L, Fazleabas A. Notch1 mediates uterine stromal differentiation and is critical for complete decidualization in the mouse. FASEB J 2011; 26:282-94. [PMID: 21990372 DOI: 10.1096/fj.11-184663] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Uterine receptivity implies a dialogue between the hormonally primed maternal endometrium and the free-floating blastocyst. Endometrial stromal cells proliferate, avert apoptosis, and undergo decidualization in preparation for implantation; however, the molecular mechanisms that underlie differentiation into the decidual phenotype remain largely undefined. The Notch family of transmembrane receptors transduce extracellular signals responsible for cell survival, cell-to-cell communication, and differentiation, all fundamental processes for decidualization and pregnancy. Using a murine artificial decidualization model, pharmacological inhibition of Notch signaling by γ-secretase inhibition resulted in a significantly decreased deciduoma. Furthermore, a progesterone receptor (PR)-Cre Notch1 bigenic (Notch1(d/d)) confirmed a Notch1-dependent hypomorphic decidual phenotype. Microarray and pathway analysis, following Notch1 ablation, demonstrated significantly altered signaling repertoire. Concomitantly, hierarchical clustering demonstrated Notch1-dependent differences in gene expression. Uteri deprived of Notch1 signaling demonstrated decreased cellular proliferation; namely, reduced proliferation-specific antigen, Ki67, altered p21, cdk6, and cyclinD activity and an increased apoptotic-profile, cleaved caspase-3, Bad, and attenuated Bcl2. The results demonstrate that the preimplantation uterus relies on Notch signaling to inhibit apoptosis of stromal fibroblasts and regulate cell cycle progression, which together promotes successful decidualization. In summary, Notch1 signaling modulates multiple signaling mechanisms crucial for decidualization and these studies provide additional perspectives to the coordination of multiple signaling modalities required during decidualization.
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Affiliation(s)
- Yalda Afshar
- Department of Physiology and Biophysics, University of Illinois, Chicago, IL, USA
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42
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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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43
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Saito T, Suemoto T, Brouwers N, Sleegers K, Funamoto S, Mihira N, Matsuba Y, Yamada K, Nilsson P, Takano J, Nishimura M, Iwata N, Van Broeckhoven C, Ihara Y, Saido TC. Potent amyloidogenicity and pathogenicity of Aβ43. Nat Neurosci 2011; 14:1023-32. [PMID: 21725313 DOI: 10.1038/nn.2858] [Citation(s) in RCA: 215] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 05/13/2011] [Indexed: 11/09/2022]
Abstract
The amyloid-β peptide Aβ42 is known to be a primary amyloidogenic and pathogenic agent in Alzheimer's disease. However, the role of Aβ43, which is found just as frequently in the brains of affected individuals, remains unresolved. We generated knock-in mice containing a pathogenic presenilin-1 R278I mutation that causes overproduction of Aβ43. Homozygosity was embryonic lethal, indicating that the mutation involves a loss of function. Crossing amyloid precursor protein transgenic mice with heterozygous mutant mice resulted in elevated Aβ43, impairment of short-term memory and acceleration of amyloid-β pathology, which accompanied pronounced accumulation of Aβ43 in plaque cores similar in biochemical composition to those observed in the brains of affected individuals. Consistently, Aβ43 showed a higher propensity to aggregate and was more neurotoxic than Aβ42. Other pathogenic presenilin mutations also caused overproduction of Aβ43 in a manner correlating with Aβ42 and with the age of disease onset. These findings indicate that Aβ43, an overlooked species, is potently amyloidogenic, neurotoxic and abundant in vivo.
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Affiliation(s)
- Takashi Saito
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, Wako-shi, Saitama, Japan
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44
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Barthet G, Shioi J, Shao Z, Ren Y, Georgakopoulos A, Robakis NK. Inhibitors of γ-secretase stabilize the complex and differentially affect processing of amyloid precursor protein and other substrates. FASEB J 2011; 25:2937-46. [PMID: 21597003 DOI: 10.1096/fj.11-183806] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
γ-Secretase inhibitors (GSIs) are drugs used in research to inhibit production of Aβ and in clinical trials to treat Alzheimer's disease (AD). They inhibit proteolytic activities of γ-secretase noncompetitively by unknown mechanisms. Here, we used cortical neuronal cultures expressing endogenous levels of enzymes and substrates to study the effects of GSIs on the structure and function of γ-secretase. We show that GSIs stabilize the interactions between the C-terminal fragment of presenilin (PS-CTF), the central component of the γ-secretase complex, and its partners the APH-1/nicastrin and PS1-NTF/PEN-2 subcomplexes. This stabilization dose-dependently correlates with inhibition of N-cadherin cleavage, a process limited by enzyme availability. In contrast, production of amyloid precursor protein (APP) intracellular domain (AICD) is insensitive to low concentrations of GSIs and is limited by substrate availability. Interestingly, APP is processed by both PS1- and PS2-containing γ-secretase complexes, while N-cadherin and ephrinB1 are processed only by PS1-containing complexes. Paradoxically, low concentrations of GSIs specifically increased the levels of Aβ without affecting its catabolism, indicating increased Aβ production. Our data reveal a mechanism of γ-secretase inhibition by GSIs and provide evidence that distinct γ-secretase complexes process specific substrates. Furthermore, our observations have implications for GSIs as therapeutics because processing of functionally important substrates may be inhibited at lower concentrations than Aβ.
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Affiliation(s)
- Gael Barthet
- Department of Psychiatry, Mt. Sinai School of Medicine, New York University, New York, NY 10029, USA
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45
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Lichtenthaler SF, Haass C, Steiner H. Regulated intramembrane proteolysis--lessons from amyloid precursor protein processing. J Neurochem 2011; 117:779-96. [PMID: 21413990 DOI: 10.1111/j.1471-4159.2011.07248.x] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Regulated intramembrane proteolysis (RIP) controls the communication between cells and the extracellular environment. RIP is essential in the nervous system, but also in other tissues. In the RIP process, a membrane protein typically undergoes two consecutive cleavages. The first one results in the shedding of its ectodomain. The second one occurs within its transmembrane domain, resulting in secretion of a small peptide and the release of the intracellular domain into the cytosol. The proteolytic cleavage fragments act as versatile signaling molecules or are further degraded. An increasing number of membrane proteins undergo RIP. These include growth factors, cytokines, cell adhesion proteins, receptors, viral proteins and signal peptides. A dysregulation of RIP is found in diseases, such as leukemia and Alzheimer's disease. One of the first RIP substrates discovered was the amyloid precursor protein (APP). RIP processing of APP controls the generation of the amyloid β-peptide, which is believed to cause Alzheimer's disease. Focusing on APP as the best-studied RIP substrate, this review describes the function and mechanism of the APP RIP proteases with the goal to elucidate cellular mechanisms and common principles of the RIP process in general.
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Affiliation(s)
- Stefan F Lichtenthaler
- DZNE-German Center for Neurodegenerative Diseases, Adolf-Butenandt-Institute, Biochemistry, Ludwig-Maximilians-University, Munich, Germany
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46
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Kaden D, Munter LM, Reif B, Multhaup G. The amyloid precursor protein and its homologues: structural and functional aspects of native and pathogenic oligomerization. Eur J Cell Biol 2011; 91:234-9. [PMID: 21459473 DOI: 10.1016/j.ejcb.2011.01.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 01/24/2011] [Accepted: 01/24/2011] [Indexed: 12/20/2022] Open
Abstract
Over the last 25 years, remarkable progress has been made not only in identifying key molecules of Alzheimer's disease but also in understanding their meaning in the pathogenic state. One hallmark of Alzheimer pathology is the amyloid plaque. A major component of the extracellular deposit is the amyloid-β (Aβ) peptide which is generated from its larger precursor molecule, i.e., the amyloid precursor protein (APP) by consecutive cleavages. Processing is exerted by two enzymes, i.e., the β-secretase and the γ-secretase. We and others have found that the self-association of the amyloid peptide and the dimerization and oligomerization of these proteins is a key factor under native and pathogenic conditions. In particular, the Aβ homodimer represents a nidus for plaque formation and a well defined therapeutic target. Further, dimerization of the APP was reported to increase generation of toxic Aβ whereas heterodimerization with its homologues amyloid precursor like proteins (APLP1 and APLP2) decreased Aβ formation. This review mainly focuses on structural features of the homophilic and heterophilic interactions among APP family proteins. The proposed contact sites are described and the consequences of protein dimerization on their functions and in the pathogenesis of Alzheimer's disease are discussed.
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Affiliation(s)
- Daniela Kaden
- Institut für Chemie und Biochemie, Freie Universität Berlin, Thielallee 63, 14195 Berlin, Germany
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47
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Wang H, Barreyro L, Provasi D, Djemil I, Torres-Arancivia C, Filizola M, Ubarretxena-Belandia I. Molecular determinants and thermodynamics of the amyloid precursor protein transmembrane domain implicated in Alzheimer's disease. J Mol Biol 2011; 408:879-95. [PMID: 21440556 DOI: 10.1016/j.jmb.2011.03.028] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 03/03/2011] [Accepted: 03/14/2011] [Indexed: 01/02/2023]
Abstract
The deposition of toxic amyloid-β (Aβ) peptide aggregates in the brain is a hallmark of Alzheimer's disease. The intramembrane proteolysis by γ-secretase of the amyloid precursor protein β-carboxy-terminal fragment (APP-βCTF) constitutes the final step in the production of Aβ peptides. Mounting evidence suggests that APP-βCTF is a transmembrane domain (TMD) dimer, and that dimerization might modulate the production of Aβ species that are prone to aggregation and are therefore most toxic. We combined experimental and computational approaches to study the molecular determinants and thermodynamics of APP-βCTF dimerization, and we produced a unifying structural model that reconciles much of the published data. Using a cell assay that exploits a dimerization-dependent activator of transcription, we identified specific dimerization-affecting mutations located mostly at the N-terminus of the TMD of APP-βCTF. The ability of selected mutants to affect the dimerization of full-length APP-βCTF was confirmed by fluorescence resonance energy transfer experiments. Free-energy estimates of the wild type and mutants of the TMD of APP-βCTF derived from enhanced molecular dynamics simulations showed that the dimeric state is composed of different arrangements, in which either (709)GXXXA(713) or (700)GXXXG(704)GXXXG(708) interaction motifs can engage in symmetric or asymmetric associations. Mutations along the TMD of APP-βCTF were found to modulate the relative free energy of the dimeric configurations and to differently affect the distribution of interfaces within the dimeric state. This observation might have important biological implications, since dimers with a different arrangement of the transmembrane helices are likely to be recognized differently by γ-secretase and to lead to a variation in Aβ levels.
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Affiliation(s)
- Hao Wang
- Department of Structural and Chemical Biology, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA
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48
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Pistollato F, Rampazzo E, Persano L, Abbadi S, Frasson C, Denaro L, D'Avella D, Panchision DM, Della Puppa A, Scienza R, Basso G. Interaction of hypoxia-inducible factor-1α and Notch signaling regulates medulloblastoma precursor proliferation and fate. Stem Cells 2011; 28:1918-29. [PMID: 20827750 DOI: 10.1002/stem.518] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Medulloblastoma (MDB) is the most common brain malignancy of childhood. It is currently thought that MDB arises from aberrantly functioning stem cells in the cerebellum that fail to maintain proper control of self-renewal. Additionally, it has been reported that MDB cells display higher endogenous Notch signaling activation, known to promote the survival and proliferation of neoplastic neural stem cells and to inhibit their differentiation. Although interaction between hypoxia-inducible factor-1α (HIF-1α) and Notch signaling is required to maintain normal neural precursors in an undifferentiated state, an interaction has not been identified in MDB. Here, we investigate whether hypoxia, through HIF-1α stabilization, modulates Notch1 signaling in primary MDB-derived cells. Our results indicate that MDB-derived precursor cells require hypoxic conditions for in vitro expansion, whereas acute exposure to 20% oxygen induces tumor cell differentiation and death through inhibition of Notch signaling. Importantly, stimulating Notch1 activation with its ligand Dll4 under hypoxic conditions leads to expansion of MDB-derived CD133(+) and nestin(+) precursors, suggesting a regulatory effect on stem cells. In contrast, MDB cells undergo neuronal differentiation when treated with γ-secretase inhibitor, which prevents Notch activation. These results suggest that hypoxia, by maintaining Notch1 in its active form, preserves MDB stem cell viability and expansion.
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Affiliation(s)
- Francesca Pistollato
- SSD Clinical and Experimental Hematology, Department of Paediatrics, University of Padova, Padova, Italy
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Wolfe MS. Structure, mechanism and inhibition of gamma-secretase and presenilin-like proteases. Biol Chem 2011; 391:839-47. [PMID: 20482315 DOI: 10.1515/bc.2010.086] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Presenilin is the catalytic component of gamma-secretase, a complex aspartyl protease and a founding member of intramembrane-cleaving proteases. gamma-Secretase is involved in the pathogenesis of Alzheimer's disease and a top target for therapeutic intervention. However, the protease complex processes a variety of transmembrane substrates, including the Notch receptor, raising concerns about toxicity. Nevertheless, gamma-secretase inhibitors and modulators have been identified that allow Notch processing and signaling to continue, and promising compounds are entering clinical trials. Molecular and biochemical studies offer a model for how this protease hydrolyzes transmembrane domains in the confines of the lipid bilayer. Progress has also been made toward structure elucidation of presenilin and the gamma-secretase complex by electron microscopy as well as by studying cysteine-mutant presenilins. The signal peptide peptidase (SPP) family of proteases are distantly related to presenilins. However, the SPPs work as single polypeptides without the need for cofactors and otherwise appear to be simple model systems for presenilin in the gamma-secretase complex. SPP biology, structure, and inhibition will also be discussed.
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Affiliation(s)
- Michael S Wolfe
- Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Abstract
Alzheimer disease (AD) is the most common causes of neurodegenerative disorder in the elderly individuals. Clinically, patients initially present with short-term memory loss, subsequently followed by executive dysfunction, confusion, agitation, and behavioral disturbances. Three causative genes have been associated with autosomal dominant familial AD (APP, PSEN1, and PSEN2) and 1 genetic risk factor (APOEε4 allele). Identification of these genes has led to a number of animal models that have been useful to study the pathogenesis underlying AD. In this article, we provide an overview of the clinical and genetic features of AD.
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Affiliation(s)
- Lynn M. Bekris
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Chang-En Yu
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - Thomas D. Bird
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Debby W. Tsuang
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
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