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Hwang DJ, Choi DH, Kwon KC, Kim EH, Kim TK, Koo JH, Cho JY. Exercise Reverses Amyloid Beta-Peptide-mediated Cognitive Deficits in Alzheimer's Disease Mice Expressing Mutant Presenilin-2. Med Sci Sports Exerc 2021; 54:551-565. [PMID: 34816813 DOI: 10.1249/mss.0000000000002834] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE The molecular mechanisms by which physical exercise produces beneficial effects on pathological features and behavioral symptoms of Alzheimer's disease (AD) are not well understood. Herein, we examined whether regular moderate exercise could improve cognitive function and produce transcriptomic responses in the brain. METHODS Four groups of mice were studied: non-transgenic control (Non-Tg), mice expressing the human presenilin-2 wild type (Tg-PS2w), mice expressing the human presenilin-2 with the N141I mutation (Tg-PS2m), and Tg-PS2m that were subjected to treadmill exercise (TE) at a speed of 10 m/min for 50 min/day, 5 days/week, for 6 weeks (Tg-PS2m/Ex). RESULTS Tg-PS2m/Ex mice exhibited increased preference in exploring a novel object than Tg-PS2m in the novel object recognition test (NORT), whereas differences observed in the water maze test and passive avoidance test were not significant. Western blot and histological analyses using amyloid oligomer (A11) and Aβ (6E10) antibody indicated that amyloid oligomer-reactive bands and plaque deposition in the hippocampus were reduced, though not significantly, after TE. Transcriptomic (RNA-sequencing) analysis and subsequent protein analysis revealed that the cell cycle regulatory gene, Cdc28 protein kinase regulatory subunit 2 (Cks2), was decreased, and the cell cycle- and apoptotic cell death-related factors, including cyclin D1, proliferating cell nuclear antigen, and cleaved caspase-3 were increased in the hippocampus of Tg-PS2m, whereas TE reversed their altered expression. CONCLUSION These results support the hypothesis that the pathological features and behavioral symptoms of AD caused by accumulation of amyloid beta-peptide in hippocampus, causing aberrant cell cycle re-entry and apoptosis, can be reversed by regular exercise.
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Affiliation(s)
- Dong-Joo Hwang
- Exercise Biochemistry Laboratory, Korea National Sport University, Seoul, Republic of Korea Department of Physical Education, Dongguk University, Seoul, Republic of Korea
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Almendáriz-Palacios C, Gillespie ZE, Janzen M, Martinez V, Bridger JM, Harkness TAA, Mousseau DD, Eskiw CH. The Nuclear Lamina: Protein Accumulation and Disease. Biomedicines 2020; 8:E188. [PMID: 32630170 PMCID: PMC7400325 DOI: 10.3390/biomedicines8070188] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 02/06/2023] Open
Abstract
Cellular health is reliant on proteostasis-the maintenance of protein levels regulated through multiple pathways modulating protein synthesis, degradation and clearance. Loss of proteostasis results in serious disease and is associated with aging. One proteinaceous structure underlying the nuclear envelope-the nuclear lamina-coordinates essential processes including DNA repair, genome organization and epigenetic and transcriptional regulation. Loss of proteostasis within the nuclear lamina results in the accumulation of proteins, disrupting these essential functions, either via direct interactions of protein aggregates within the lamina or by altering systems that maintain lamina structure. Here we discuss the links between proteostasis and disease of the nuclear lamina, as well as how manipulating specific proteostatic pathways involved in protein clearance could improve cellular health and prevent/reverse disease.
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Affiliation(s)
- Carla Almendáriz-Palacios
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (C.A.-P.); (V.M.)
| | - Zoe E. Gillespie
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (Z.E.G.); (M.J.); (T.A.A.H.)
| | - Matthew Janzen
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (Z.E.G.); (M.J.); (T.A.A.H.)
| | - Valeria Martinez
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (C.A.-P.); (V.M.)
| | - Joanna M. Bridger
- Centre for Genome Engineering and Maintenance, College of Health, Life and Medical Sciences, Brunel University London, Kingston Lane, Uxbridge UB8 3PH, UK;
| | - Troy A. A. Harkness
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (Z.E.G.); (M.J.); (T.A.A.H.)
| | - Darrell D. Mousseau
- Cell Signalling Laboratory, Department of Psychiatry, University of Saskatchewan, Saskatoon, SK S7N 5A5, Canada;
| | - Christopher H. Eskiw
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (C.A.-P.); (V.M.)
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada; (Z.E.G.); (M.J.); (T.A.A.H.)
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3
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Ugolino J, Dziki KM, Kim A, Wu JJ, Vogel BE, Monteiro MJ. Overexpression of human Atp13a2Isoform-1 protein protects cells against manganese and starvation-induced toxicity. PLoS One 2019; 14:e0220849. [PMID: 31393918 PMCID: PMC6687281 DOI: 10.1371/journal.pone.0220849] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 07/24/2019] [Indexed: 12/20/2022] Open
Abstract
Mutations in ATP13A2 cause Kufor-Rakeb syndrome (KRS), a juvenile form of Parkinson's disease (PD) with dementia. However, the mechanisms by which mutations in ATP13A2 cause KRS is not understood. The mutations lead to misfolding of the translated Atp13a2 protein and its premature degradation in the endoplasmic reticulum, never reaching the lysosome where the protein is thought to function. Atp13a2 is a P-type ATPase, a class of proteins that function in ion transport. Indeed, studies of human, mouse, and yeast Atp13a2 proteins suggest a possible involvement in regulation of heavy metal toxicity. Here we report on the cytoprotective function of Atp13a2 on HeLa cells and dopamine neurons of Caenorhabditis elegans (C. elegans). HeLa cells stably overexpressing V5- tagged Atp13a2Isoform-1 protein were more resistant to elevated manganese exposure and to starvation-induced cell death compared to cells not overexpressing the protein. Because PD is characterized by loss of dopamine neurons, we generated transgenic C. elegans expressing GFP-tagged human Atp13a2 protein in dopamine neurons. The transgenic animals exhibited higher resistance to dopamine neuron degeneration after acute exposure to manganese compared to nematodes that expressed GFP alone. The results suggest Atp13a2 Isoform-1 protein confers cytoprotection against toxic insults, including those that cause PD syndromes.
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Affiliation(s)
- Janet Ugolino
- Biochemistry and Molecular Biology Graduate Program, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Kristina M. Dziki
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Annette Kim
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Josephine J. Wu
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Bruce E. Vogel
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Mervyn J. Monteiro
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
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4
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Naranjo R, González P, Lopez-Hurtado A, Dopazo XM, Mellström B, Naranjo JR. Inhibition of the Neuronal Calcium Sensor DREAM Modulates Presenilin-2 Endoproteolysis. Front Mol Neurosci 2018; 11:449. [PMID: 30559648 PMCID: PMC6287014 DOI: 10.3389/fnmol.2018.00449] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 11/21/2018] [Indexed: 11/14/2022] Open
Abstract
Deregulated intracellular Ca2+ and protein homeostasis underlie synaptic dysfunction and are common features in neurodegenerative diseases. DREAM, also known as calsenilin or KChIP-3, is a multifunctional Ca2+ binding protein of the neuronal calcium sensor superfamily with specific functions through protein-DNA and protein-protein interactions. Small-molecules able to bind DREAM, like the anti-diabetic drug repaglinide, disrupt some of the interactions with other proteins and modulate DREAM activity on Kv4 channels or on the processing of activating transcription factor 6 (ATF6). Here, we show the interaction of endogenous DREAM and presenilin-2 (PS2) in mouse brain and, using DREAM deficient mice or transgenic mice overexpressing a dominant active DREAM (daDREAM) mutant in the brain, we provide genetic evidence of the role of DREAM in the endoproteolysis of endogenous PS2. We show that repaglinide disrupts the interaction between DREAM and the C-terminal PS2 fragment (Ct-PS2) by coimmunoprecipitation assays. Exposure to sub-micromolar concentrations of repaglinide reduces the levels of Ct-PS2 fragment in N2a neuroblastoma cells. These results suggest that the interaction between DREAM and PS2 may represent a new target for modulation of PS2 processing, which could have therapeutic potential in Alzheimer’s disease (AD) treatment.
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Affiliation(s)
- Rocío Naranjo
- Spanish Network for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain.,National Biotechnology Center (CNB), CSIC, Madrid, Spain
| | - Paz González
- Spanish Network for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain.,National Biotechnology Center (CNB), CSIC, Madrid, Spain
| | - Alejandro Lopez-Hurtado
- Spanish Network for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain.,National Biotechnology Center (CNB), CSIC, Madrid, Spain
| | - Xosé M Dopazo
- Spanish Network for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain.,National Biotechnology Center (CNB), CSIC, Madrid, Spain
| | - Britt Mellström
- Spanish Network for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain.,National Biotechnology Center (CNB), CSIC, Madrid, Spain
| | - José R Naranjo
- Spanish Network for Biomedical Research in Neurodegenerative Diseases (CIBERNED), ISCIII, Madrid, Spain.,National Biotechnology Center (CNB), CSIC, Madrid, Spain
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5
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Overexpression of N141I PS2 increases γ-secretase activity through up-regulation of Presenilin and Pen-2 in brain mitochondria of NSE/hPS2m transgenic mice. Lab Anim Res 2016; 32:249-256. [PMID: 28053619 PMCID: PMC5206232 DOI: 10.5625/lar.2016.32.4.249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 12/03/2016] [Accepted: 12/06/2016] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is known to induce alterations of mitochondrial function such as elevation of oxidative stress and activation of apopotosis. The aim of this study was to investigate the effects of human Presenilin 2 mutant (hPS2m) overexpression on the γ-secretase complex in the mitochondrial fraction. To achieve this, alterations of γ-secretase complex expression and activity were detected in the mitochondrial fraction derived from brains of NSE/hPS2m Tg mice and Non-Tg mice. Herein, the following were observed: i) overexpression of the hPS2m gene significantly up-regulated the deposition of Aβ-42 peptides in the hippocampus and cortex of brain, ii) overexpression of hPS2m protein induced alterations of γ-secretase components such as main component protein and activator protein but not stabilization-related proteins, iii) changes in γ-secretase components induced by overexpression of hPS2m protein up-regulated γ-secretase activity in the mitochondrial fraction, and iv) elevation of γ-secretase activity induced production of Aβ-42 peptides in the mitochondrial fraction. Based on these observations, these results indicate that alteration of γ-secretase activity in cells upon overexpression of hPS2m is tightly linked to mitochondrial dysfunction under the specific physiological and pathological conditions of AD.
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6
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Cuajungco MP, Lees GJ, Kydd RR, Tanzi RE, Bush AI. Zinc and Alzheimer's Disease: An Update. Nutr Neurosci 2016; 2:191-208. [DOI: 10.1080/1028415x.1999.11747277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Duggan SP, McCarthy JV. Beyond γ-secretase activity: The multifunctional nature of presenilins in cell signalling pathways. Cell Signal 2015; 28:1-11. [PMID: 26498858 DOI: 10.1016/j.cellsig.2015.10.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 10/19/2015] [Indexed: 01/24/2023]
Abstract
The presenilins are the catalytic subunit of the membrane-embedded tetrameric γ-secretase protease complexes. More that 90 transmembrane proteins have been reported to be γ-secretase substrates, including the widely studied amyloid precursor protein (APP) and the Notch receptor, which are precursors for the generation of amyloid-β peptides and biologically active APP intracellular domain (AICD) and Notch intracellular domain (NICD). The diversity of γ-secretase substrates highlights the importance of presenilin-dependent γ-secretase protease activities as a regulatory mechanism in a range of biological systems. However, there is also a growing body of evidence that supports the existence of γ-secretase-independent functions for the presenilins in the regulation and progression of an array of cell signalling pathways. In this review, we will present an overview of current literature that proposes evolutionarily conserved presenilin functions outside of the γ-secretase complex, with a focus on the suggested role of the presenilins in the regulation of Wnt/β-catenin signalling, protein trafficking and degradation, calcium homeostasis and apoptosis.
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Affiliation(s)
- Stephen P Duggan
- Signal Transduction Laboratory, School of Biochemistry & Cell Biology, ABCRF, Western Gateway Building, University College Cork, Cork, Ireland
| | - Justin V McCarthy
- Signal Transduction Laboratory, School of Biochemistry & Cell Biology, ABCRF, Western Gateway Building, University College Cork, Cork, Ireland.
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8
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Hooghiemstra AM, Eggermont LHP, Scheltens P, van der Flier WM, Scherder EJA. Exercise and early-onset Alzheimer's disease: theoretical considerations. Dement Geriatr Cogn Dis Extra 2012; 2:132-45. [PMID: 22590474 PMCID: PMC3347875 DOI: 10.1159/000335493] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND/AIMS Although studies show a negative relationship between physical activity and the risk for cognitive impairment and late-onset Alzheimer's disease, studies concerning early-onset Alzheimer's disease (EOAD) are lacking. This review aims to justify the value of exercise interventions in EOAD by providing theoretical considerations that include neurobiological processes. METHODS A literature search on key words related to early-onset dementia, exercise, imaging, neurobiological mechanisms, and cognitive reserve was performed. RESULTS/CONCLUSION Brain regions and neurobiological processes contributing to the positive effects of exercise are affected in EOAD and, thus, provide theoretical support for exercise interventions in EOAD. Finally, we present the design of a randomized controlled trial currently being conducted in early-onset dementia patients.
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9
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Hu Y, Peng Y, Long Y, Xu S, Feng N, Wang L, Wang X. Potassium 2-(1-hydroxypentyl)-benzoate attenuated hydrogen peroxide-induced apoptosis in neuroblastoma SK-N-SH cells. Eur J Pharmacol 2012; 680:49-54. [PMID: 22329894 DOI: 10.1016/j.ejphar.2012.01.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 01/19/2012] [Accepted: 01/24/2012] [Indexed: 10/14/2022]
Abstract
Potassium 2-(1-hydroxypentyl)-benzoate (dl-PHPB) has been shown to have potent neuroprotective effects, such as reducing the infarct volume and improving neurobehavioral deficits in the transient focal cerebral ischemic rat model. The present study is to evaluate the neuroprotective effect of dl-PHPB on hydrogen peroxide (H(2)O(2))-induced apoptosis and the possible mechanism in the human neuroblastoma SK-N-SH cells. Our results showed that dl-PHPB significantly attenuated H(2)O(2)-induced cell death, and reduced neuronal apoptosis. Dl-PHPB partially reversed the decrease of B-cell CLL/lymphoma 2 (Bcl-2) protein level induced by H(2)O(2). Furthermore, dl-PHPB inhibited the elevation of pro-apoptotic Bcl-2-associated X protein (Bax) and caspase3, and alleviated the down-regulation of protein kinase C alpha (PKCα). The PKC inhibitor, Calphostin C significantly attenuated the protective effects of dl-PHPB. The findings suggest that dl-PHPB may protect neurons against H(2)O(2)-induced apoptosis by modulating apoptosis-related proteins, and PKC signaling pathway may be involved in the neuroprotection of dl-PHPB.
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Affiliation(s)
- Yanli Hu
- State Key laboratory of Bioactive Substances and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College,Beijing 100050, China
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10
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Müller M, Cárdenas C, Mei L, Cheung KH, Foskett JK. Constitutive cAMP response element binding protein (CREB) activation by Alzheimer's disease presenilin-driven inositol trisphosphate receptor (InsP3R) Ca2+ signaling. Proc Natl Acad Sci U S A 2011; 108:13293-8. [PMID: 21784978 PMCID: PMC3156223 DOI: 10.1073/pnas.1109297108] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Mutations in presenilins (PS) account for most early-onset familial Alzheimer's disease (FAD). Accumulating evidence suggests that disrupted Ca(2+) signaling may play a proximal role in FAD specifically, and Alzheimer's disease (AD) more generally, but its links to the pathogenesis of AD are obscure. Here we demonstrate that expression of FAD mutant PS constitutively activates the transcription factor cAMP response element binding protein (CREB) and CREB target gene expression in cultured neuronal cells and AD mouse models. Constitutive CREB activation was associated with and dependent on constitutive activation of Ca(2+)/CaM kinase kinase β and CaM kinase IV (CaMKIV). Depletion of endoplasmic reticulum Ca(2+) stores or plasma membrane phosphatidylinositol-bisphosphate and pharmacologic inhibition or knockdown of the expression of the inositol trisphosphate receptor (InsP(3)R) Ca(2+) release channel each abolished FAD PS-associated constitutive CaMKIV and CREB phosphorylation. CREB and CaMKIV phosphorylation and CREB target gene expression, including nitric oxide synthase and c-fos, were enhanced in brains of M146V-KI and 3xTg-AD mice expressing FAD mutant PS1 knocked into the mouse locus. FAD mutant PS-expressing cells demonstrated enhanced cell death and sensitivity to Aβ toxicity, which were normalized by interfering with the InsP(3)R-CAMKIV-CREB pathway. Thus, constitutive CREB phosphorylation by exaggerated InsP(3)R Ca(2+) signaling in FAD PS-expressing cells may represent a signaling pathway involved in the pathogenesis of AD.
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Affiliation(s)
| | | | | | | | - J. Kevin Foskett
- Departments of Physiology and
- Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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Niikura T, Tajima H, Kita Y. Neuronal cell death in Alzheimer's disease and a neuroprotective factor, humanin. Curr Neuropharmacol 2010; 4:139-47. [PMID: 18615127 DOI: 10.2174/157015906776359577] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 11/09/2005] [Accepted: 12/08/2005] [Indexed: 11/22/2022] Open
Abstract
Brain atrophy caused by neuronal loss is a prominent pathological feature of Alzheimer's disease (AD). Amyloid beta (Abeta), the major component of senile plaques, is considered to play a central role in neuronal cell death. In addition to removal of the toxic Abeta, direct suppression of neuronal loss is an essential part of AD treatment; however, no such neuroprotective therapies have been developed. Excess amount of Abeta evokes multiple cytotoxic mechanisms, involving increase of the intracellular Ca(2+) level, oxidative stress, and receptor-mediated activation of cell-death cascades. Such diversity in cytotoxic mechanisms induced by Abeta clearly indicates a complex nature of the AD-related neuronal cell death. We have identified a 24-residue peptide, Humanin (HN), which suppresses in vitro neuronal cell death caused by all AD-related insults, including Abeta, so far tested. The anti-AD effect of HN has been further confirmed in vivo using mice with Abeta-induced amnesia. Altogether, such potent neuroprotective activity of HN against AD-relevant cytotoxicity both in vitro and in vivo suggests the potential clinical applications of HN in novel AD therapies aimed at controlling neuronal death.
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Affiliation(s)
- Takako Niikura
- Department of Pharmacology, KEIO University School of Medicine, 35 Shinanomachi, Tokyo 160-8582, Japan.
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12
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Rothenberg C, Srinivasan D, Mah L, Kaushik S, Peterhoff CM, Ugolino J, Fang S, Cuervo AM, Nixon RA, Monteiro MJ. Ubiquilin functions in autophagy and is degraded by chaperone-mediated autophagy. Hum Mol Genet 2010; 19:3219-32. [PMID: 20529957 DOI: 10.1093/hmg/ddq231] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Autophagy is the process by which organelles and portions of the cytoplasm are degraded in lysosomes. Several different forms of autophagy are known that are distinguishable chiefly by the mode in which cargo is delivered to the lysosome for degradation. Ubiquilin was recently reported to regulate macroautophagy, the form of autophagy in which cytosolic cargo is packaged in a double-membrane structure or autophagosome that fuses with lysosomes for degradation. We confirm here using different morphological and biochemical procedures that ubiquilin is present in autophagosomes in HeLa cells and in brain and liver tissue of mouse. Coimmunoprecipitation studies indicated that ubiquilin binds the autophagosome marker LC3 in a complex and that reduction of ubiquilin expression reduces autophagosome formation, which correlates with a reduction in maturation of LC3-I to the LC3-II form of the protein. We found that ubiquilin is degraded during both macroautophagy and during chaperone-mediated autophagy (CMA), the latter of which involves the active transport of proteins into lysosomes. We discuss the implication of this degradation in mediating cross-talk between macroautophagy and CMA. Finally, we demonstrate that ubiquilin protects cells against starvation-induced cell death propagated by overexpression of mutant Alzheimer's disease PS2N141I protein and green fluorescent protein (GFP)-huntingtin exon-1 fusion protein containing 74 polyglutamines.
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Affiliation(s)
- Cara Rothenberg
- Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, 725 West Lombard Street, Baltimore, MD 21201, USA
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13
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Dunys J, Sevalle J, Giaime E, Pardossi-Piquard R, Vitek MP, Renbaum P, Levy-Lahad E, Zhang YW, Xu H, Checler F, da Costa CA. p53-dependent control of transactivation of the Pen2 promoter by presenilins. J Cell Sci 2010; 122:4003-8. [PMID: 19889971 DOI: 10.1242/jcs.051169] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The senile plaques found in the brains of patients with Alzheimer's disease are mainly due to the accumulation of amyloid beta-peptides (A beta) that are liberated by gamma-secretase, a high molecular weight complex including presenilins, PEN-2, APH-1 and nicastrin. The depletion of each of these proteins disrupts the complex assembly into a functional protease. Here, we describe another level of regulation of this multimeric protease. The depletion of both presenilins drastically reduces Pen2 mRNA levels and its promoter transactivation. Furthermore, overexpression of presenilin-1 lowers Pen2 promoter transactivation, a phenotype abolished by a double mutation known to prevent presenilin-dependent gamma-secretase activity. PEN-2 expression is decreased by depletion of beta-amyloid precursor protein (APP) and increased by the APP intracellular domain (AICD). We show that AICD and APP complement for Pen2 mRNA levels in APP/APLP1-2 knockout fibroblasts. Interestingly, overexpression of presenilin-2 greatly increases Pen2 promoter transactivation. The opposite effect triggered by both presenilins was reminiscent of our previous study, which showed that these two proteins elicit antagonistic effects on p53. Therefore, we examined the contribution of p53 on Pen2 transcription. Pen2 promoter transactivation, and Pen2 mRNA and protein levels were drastically reduced in p53(-/-) fibroblasts. Furthermore, PEN-2 expression could be rescued by p53 complementation in p53- and APP-deficient cells. Interestingly, PEN-2 expression was also reduced in p53-deficient mouse brain. Overall, our study describes a p53-dependent regulation of PEN-2 expression by other members of the gamma-secretase complex, namely presenilins.
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Affiliation(s)
- Julie Dunys
- Institut de Pharmacologie Moléculaire et Cellulaire of Centre National de la Recherche Scientifique and Institut de NeuroMédecine Moléculaire, Equipe labellisée Fondation pour la Recherche Médicale, Valbonne, France
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14
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Bulat N, Widmann C. Caspase substrates and neurodegenerative diseases. Brain Res Bull 2009; 80:251-67. [DOI: 10.1016/j.brainresbull.2009.07.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 07/08/2009] [Accepted: 07/08/2009] [Indexed: 02/08/2023]
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15
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Yuk DY, Lee YK, Nam SY, Yun YW, Hwang DY, Choi DY, Oh KW, Hong JT. Reduced anxiety in the mice expressing mutant (N141I) presenilin 2. J Neurosci Res 2009; 87:522-31. [PMID: 18803281 DOI: 10.1002/jnr.21861] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Alzheimer's disease (AD) is characterized by progressive cognitive impairment. The effect of presenilin 1 (PS1) and PS2 mutation on cognition has been well characterized in a variety of transgenic mice. However, noncognitive behaviors have not been considered in these mice. In the present study, we found that transgenic mice expressing mutant PS2 (N141I) displayed decreased anxiety behavior determined by the elevated plus maze test and the light dark box test. However, these mice showed biphasic ambulatory activity (hyperactivity followed by hypoactivity) in an open field test. Correlated well with the reduced anxiety, expression of GABA(A)alpha(1) receptor was higher whereas c-Fos was lower in the cortex, hippocampus, and amygdala of the mice expressing PS2 mutation than those of the wild-type PS2 or nontransgenic control mice. These data indicate that PS2 mutation causes reduction of anxiety, and this effect may be related to the change of the expression of GABA(A)alpha(1) receptor and c-Fos. These findings could be useful in the understanding and the treatment of AD patients.
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Affiliation(s)
- Dong Yeon Yuk
- College of Pharmacy and CBITRC, Chungbuk National University, Cheongju, Chungbuk, Korea
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16
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Yasuda D, Okuno T, Yokomizo T, Hori T, Hirota N, Hashidate T, Miyano M, Shimizu T, Nakamura M. Helix 8 of leukotriene B4type‐2 receptor is required for the folding to pass the quality control in the endoplasmic reticulum. FASEB J 2009; 23:1470-81. [DOI: 10.1096/fj.08-125385] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Daisuke Yasuda
- Department of Biochemistry and Molecular BiologyFaculty of MedicineThe University of TokyoTokyoJapan
| | - Toshiaki Okuno
- Department of Medical BiochemistryGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Takehiko Yokomizo
- Department of Medical BiochemistryGraduate School of Medical SciencesKyushu UniversityFukuokaJapan
| | - Tetsuya Hori
- Structural Biophysics LaboratoryRIKEN Harima Institute at SpringHyogo8Japan
| | - Nobuaki Hirota
- Department of Biochemistry and Molecular BiologyFaculty of MedicineThe University of TokyoTokyoJapan
| | - Tomomi Hashidate
- Department of Biochemistry and Molecular BiologyFaculty of MedicineThe University of TokyoTokyoJapan
| | - Masashi Miyano
- Structural Biophysics LaboratoryRIKEN Harima Institute at SpringHyogo8Japan
| | - Takao Shimizu
- Department of Biochemistry and Molecular BiologyFaculty of MedicineThe University of TokyoTokyoJapan
| | - Motonao Nakamura
- Department of Biochemistry and Molecular BiologyFaculty of MedicineThe University of TokyoTokyoJapan
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17
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Cell cycle re-entry mediated neurodegeneration and its treatment role in the pathogenesis of Alzheimer's disease. Neurochem Int 2008; 54:84-8. [PMID: 19114068 DOI: 10.1016/j.neuint.2008.10.013] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 10/16/2008] [Accepted: 10/20/2008] [Indexed: 11/23/2022]
Abstract
As one of the earliest pathologic changes, the aberrant re-expression of many cell cycle-related proteins and inappropriate cell cycle control in specific vulnerable neuronal populations in Alzheimer's disease (AD) is emerging as an important component in the pathogenesis leading to AD and other neurodegenerative diseases. These events are clearly representative of a true cell cycle, rather than epiphenomena of other processes since, in AD and other neurodegenerative diseases, there is a true mitotic alteration that leads to DNA replication. While the exact role of cell cycle re-entry is unclear, recent studies using cell culture and animal models strongly support the notion that the dysregulation of cell cycle in neurons leads to the development of AD-related pathology such as hyperphosphorylation of tau and amyloid-beta deposition and ultimately causes neuronal cell death. Importantly, cell cycle re-entry is also evident in mutant amyloid-beta precursor protein and tau transgenic mice and, as in human disease, occurs prior to the development of the pathological hallmarks, neurofibrillary tangles and amyloid-beta plaques. Therefore, the study of aberrant cell cycle regulation in model systems, both cellular and animal, may provide extremely important insights into the pathogenesis of AD and also serve as a means to test novel therapeutic approaches.
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18
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Hass MR, Sato C, Kopan R, Zhao G. Presenilin: RIP and beyond. Semin Cell Dev Biol 2008; 20:201-10. [PMID: 19073272 DOI: 10.1016/j.semcdb.2008.11.014] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 11/19/2008] [Accepted: 11/19/2008] [Indexed: 12/22/2022]
Abstract
Over the years the presenilins (PSENs), a family of multi-transmembrane domain proteins, have been ascribed a number of diverse potential functions. Recent in vivo evidence has supported the existence of PSEN functions beyond its well-established role in regulated intramembrane proteolysis. In this review, we will briefly discuss the ability of PSEN to modulate cellular signaling pathways through gamma-secretase cleavage of transmembrane proteins. Additionally, we will critically examine the proposed roles of PSEN in the regulation of beta-catenin function, protein trafficking, calcium regulation, and apoptosis.
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Affiliation(s)
- Matthew R Hass
- Department of Developmental Biology, Washington University School of Medicine, Saint Louis, MO, United States
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19
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Nguyen HN, Lee MS, Hwang DY, Kim YK, Yoon DY, Lee JW, Yun YP, Lee MK, Oh KW, Hong JT. Mutant presenilin 2 increased oxidative stress and p53 expression in neuronal cells. Biochem Biophys Res Commun 2007; 357:174-80. [PMID: 17418105 DOI: 10.1016/j.bbrc.2007.03.119] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2007] [Accepted: 03/20/2007] [Indexed: 10/23/2022]
Abstract
The learning and memory impairment of presenilin 2 transgenic mice was mentioned previously. In this study, exposing the presenilin 2 transfected PC12 cells to the 50 microM Abeta(25-35), 30 mM l-glutamate and 50 microM H(2)O(2) resulted in significant increase 8-oxodG and p53 levels of the cells expressing the mutant gene. The increase was also found in the mutant presenilin 2 transgenic mice brains age-dependently in comparison to that in the wild-type presenilin 2-transgenic mice and non-transgenic ones. These findings indicated that mutant presenilin 2 clearly increases oxidative stress and p53 expression, which could be implicated in promoting mutant presenilin 2-induced neurodegeneration in Alzheimer's disease, and the influence of mutant presenilin 2 in Alzheimer's disease may be brain regional and age related effects.
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Affiliation(s)
- Hong Nga Nguyen
- College of Pharmacy, CBITRC, Chungbuk National University, 12, Gaeshin-dong, Heungduk-gu, Cheongju, Chungbuk 361-763, Republic of Korea
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20
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Ford D, Monteiro M. Dimerization of ubiquilin is dependent upon the central region of the protein: evidence that the monomer, but not the dimer, is involved in binding presenilins. Biochem J 2006; 399:397-404. [PMID: 16813565 PMCID: PMC1615901 DOI: 10.1042/bj20060441] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ubiquilin proteins have been shown to interact with a wide variety of other cellular proteins, often regulating the stability and degradation of the interacting protein. Ubiquilin contains a UBL (ubiquitin-like) domain at the N-terminus and a UBA (ubiquitin-associated) domain at the C-terminus, separated by a central region containing Sti1-like repeats. Little is known about regulation of the interaction of ubiquilin with other proteins. In the present study, we show that ubiquilin is capable of forming dimers, and that dimerization requires the central region of ubiquilin, but not its UBL or the UBA domains. Furthermore, we provide evidence suggesting that monomeric ubiquilin is likely to be the active form that is involved in binding presenilin proteins. Our results provide new insight into the regulatory mechanism underlying the interaction of ubiquilin with presenilins.
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Affiliation(s)
- Diana L. Ford
- Medical Biotechnology Center, Institute for Neurodegenerative Diseases, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A., and Biochemistry and Molecular Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
| | - Mervyn J. Monteiro
- Medical Biotechnology Center, Institute for Neurodegenerative Diseases, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A., and Biochemistry and Molecular Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
- To whom correspondence should be addressed (email )
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21
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Behbahani H, Shabalina IG, Wiehager B, Concha H, Hultenby K, Petrovic N, Nedergaard J, Winblad B, Cowburn RF, Ankarcrona M. Differential role of Presenilin-1 and -2 on mitochondrial membrane potential and oxygen consumption in mouse embryonic fibroblasts. J Neurosci Res 2006; 84:891-902. [PMID: 16883555 DOI: 10.1002/jnr.20990] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Increasing evidence indicates that mitochondrial alterations contribute to the neuronal death in Alzheimer's disease (AD). Presenilin 1 (PS1) and Presenilin 2 (PS2) mutations have been shown to sensitize cells to apoptosis by mechanisms suggested to involve impaired mitochondrial function. We have previously detected active gamma-secretase complexes in mitochondria. We investigated the impact of PS/gamma-secretase on mitochondrial function using mouse embryonal fibroblasts derived from wild-type, PS1-/-, PS2-/- and PS double knock-out (PSKO) embryos. Measurements of mitochondrial membrane potential (DeltaPsim) showed a higher percentage of fully functional mitochondria in PS1-/- and PSwt as compared to PS2-/- and PSKO cells. This result was evident both in whole cell preparations and in isolated mitochondria. Interestingly, pre-treatment of isolated mitochondria with the gamma-secretase inhibitor L-685,458 resulted in a decreased population of mitochondria with high DeltaPsim in PSwt and PS1-/- cells, indicating that PS2/gamma-secretase activity can modify DeltaPsim. PS2-/- cells showed a significantly lower basal respiratory rate as compared to other cell lines. However, all cell lines demonstrated competent bioenergetic function. These data point toward a specific role of PS2/gamma-secretase activity for proper mitochondrial function and indicate interplay between PS1 and PS2 in mitochondrial functionality.
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Affiliation(s)
- Homira Behbahani
- Department of Neurobiology, Karolinska Institutet Dainippon Sumitomo Pharmaceuticals Alzheimer Center, Caring Sciences and Society, Novum, Huddinge, Sweden.
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22
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Liang J, Yin C, Doong H, Fang S, Peterhoff C, Nixon RA, Monteiro MJ. Characterization of erasin (UBXD2): a new ER protein that promotes ER-associated protein degradation. J Cell Sci 2006; 119:4011-24. [PMID: 16968747 DOI: 10.1242/jcs.03163] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Ubiquitin regulator-X (UBX) is a discrete protein domain that binds p97/valosin-containing protein (VCP), a molecular chaperone involved in diverse cell processes, including endoplasmic-reticulum-associated protein degradation (ERAD). Here we characterize a human UBX-containing protein, UBXD2, that is highly conserved in mammals, which we have renamed erasin. Biochemical fractionation, immunofluorescence and electron microscopy, and protease protection experiments suggest that erasin is an integral membrane protein of the endoplasmic reticulum and nuclear envelope with both its N- and C-termini facing the cytoplasm or nucleoplasm. Localization of GFP-tagged deletion derivatives of erasin in HeLa cells revealed that a single 21-amino-acid sequence located near the C-terminus is necessary and sufficient for localization of erasin to the endoplasmic reticulum. Immunoprecipitation and GST-pulldown experiments confirmed that erasin binds p97/VCP via its UBX domain. Additional immunoprecipitation assays indicated that erasin exists in a complex with other p97/VCP-associated factors involved in ERAD. Overexpression of erasin enhanced the degradation of the ERAD substrate CD3δ, whereas siRNA-mediated reduction of erasin expression almost completely blocked ERAD. Erasin protein levels were increased by endoplasmic reticulum stress. Immunohistochemical staining of brain tissue from patients with Alzheimer's disease and control subjects revealed that erasin accumulates preferentially in neurons undergoing neurofibrillary degeneration in Alzheimer's disease. These results suggest that erasin may be involved in ERAD and in Alzheimer's disease.
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Affiliation(s)
- Jing Liang
- Graduate Program in Molecular Medicine, and Institute for Neurodegenerative Diseases, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, USA
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23
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Nguyen HN, Son DJ, Lee JW, Hwang DY, Kim YK, Cho JS, Lee US, Yoo HS, Moon DC, Oh KW, Hong JT. Mutant presenilin 2 causes abnormality in the brain lipid profile in the development of Alzheimer’s disease. Arch Pharm Res 2006; 29:884-9. [PMID: 17121184 DOI: 10.1007/bf02973910] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mutation in the presenilin 2 (PS2mt) is known to be one of factors involved in the development of Alzheimer's disease (AD). It was recently revealed that an abnormality of lipid metabolism is a phenomenon occurring in AD. Therefore, the aim of this study was to investigate the potential relationship between the mutation of PS2 and alterations of the lipid profile within the brain. The results showed there increases in the levels of cholesterol, low density lipoprotein and triglyceride, but a decrease in the level of high density lipoprotein in brain tissues expressing mutant PS2. These findings indicated that PS2mt is involved in the abnormalities of the lipid profile, which could cause or result in the development of AD.
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Affiliation(s)
- Hong Nga Nguyen
- College of Pharmacy and CBITRC, Chungbuk National University, Cheongju 361-763, Korea
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24
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Cai C, Lin P, Cheung KH, Li N, Levchook C, Pan Z, Ferrante C, Boulianne GL, Foskett JK, Danielpour D, Ma J. The Presenilin-2 Loop Peptide Perturbs Intracellular Ca2+ Homeostasis and Accelerates Apoptosis. J Biol Chem 2006; 281:16649-55. [PMID: 16603547 DOI: 10.1074/jbc.m512026200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In cells undergoing apoptosis, a 22-amino-acid presenilin-2-loop peptide (PS2-LP, amino acids 308-329 in presenilin-2) is generated through cleavage of the carboxyl-terminal fragment of presenilin-2 by caspase-3. The impact of PS2-LP on the progression of apoptosis, however, is not known. Here we show that PS2-LP is a potent inducer of the mitochondrial-dependent cell death pathway when transduced as a fusion protein with HIV-TAT. Biochemical and functional studies demonstrate that TAT-PS2-LP can interact with the inositol 1,4,5-trisphosphate receptor and activate Ca(2+) release from the endoplasmic reticulum. These results indicate that PS2-LP-mediated alteration of intracellular Ca(2+) homeostasis may be linked to the acceleration of apoptosis. Therefore, targeting the function of PS2-LP could provide a useful therapeutic tool for the treatment of cancer and degenerative diseases.
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Affiliation(s)
- Chuanxi Cai
- Department of Physiology and Biophysics, Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
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25
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Minet E, Cosse JP, Demazy C, Raes M, Michiels C. Accumulation of the pro-apoptotic factor Bak is controlled by antagonist factor Mcl-1 availability. Apoptosis 2006; 11:1039-47. [PMID: 16547591 DOI: 10.1007/s10495-006-6650-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Apoptosis has become recognized as a crucial mechanism involved in a wide range of physiological and pathological processes. Following an initial pro-apoptotic signal, controlling phases allow the cell to reinforce or downgrade signals leading to the irrevocable entry into apoptosis. Bak (Bcl-2-antagonist killer) is a mitochondrial pore-forming pro-apoptotic effector inhibited through titration by the anti-apoptotic protein Mcl-1 (Myeloid cell leukemia-1). Viruses have taken advantage of proteasome-dependent degradation of Bak as a mechanism to prevent apoptosis in infected cells. It is not clear however whether regulation of Bak protein level is involved in other physiological processes. In this report, we show that Mcl-1 level is paralleled by Bak while a Mcl-1 non-interacting mutant of Bak does not accumulate in cells. This mechanism is proteasome independent. Following serum withdrawal, Bak accumulation becomes independent of Mcl-1 level and cells are sensitized to pro-apoptotic stimuli. Based on these results, we propose that regulation of Mcl-1-Bak steochiometry is a control mechanism used as a checkpoint to prevent or allow entry into apoptosis.
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Affiliation(s)
- E Minet
- Laboratory of Biochemistry and Cellular Biology, University of Namur, 61 rue de Bruxelles, 5000, Namur, Belgium
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26
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Kim JH, Choi S, Jung JE, Roh EJ, Kim HJ. Capacitative Ca2+ entry is involved in regulating soluble amyloid precursor protein (sAPPalpha) release mediated by muscarinic acetylcholine receptor activation in neuroblastoma SH-SY5Y cells. J Neurochem 2006; 97:245-54. [PMID: 16524374 DOI: 10.1111/j.1471-4159.2006.03734.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Previous studies have demonstrated that stimulation of phospholipase C-linked G-protein-coupled receptors, including muscarinic M1 and M3 receptors, increases the release of the soluble form of amyloid precursor protein (sAPPalpha) by alpha-secretase cleavage. In this study, we examined the involvement of capacitative Ca2+ entry (CCE) in the regulation of muscarinic acetylcholine receptor (mAChR)-dependent sAPPalpha release in neuroblastoma SH-SY5Y cells expressing abundant M3 mAChRs. The sAPPalpha release stimulated by mAChR activation was abolished by EGTA, an extracellular Ca2+ chelator, which abolished mAChR-mediated Ca2+ influx without affecting Ca2+ mobilization from intracellular stores. However, mAChR-mediated sAPPalpha release was not inhibited by thapsigargin, which increases basal [Ca2+]i by depletion of Ca2+ from intracellular stores. While these results indicate that the mAChR-mediated increase in sAPPalpha release is regulated largely by Ca2+ influx rather than by Ca2+ mobilization from intracellular stores, we further investigated the Ca2+ entry mechanisms regulating this phenomenon. CCE inhibitors such as Gd3+, SKF96365, and 2-aminoethoxydiphenyl borane (2-APB), dose dependently reduced both Ca2+ influx and sAPPalpha release stimulated by mAChR activation, whereas inhibition of voltage-dependent Ca2+ channels, Na+/Ca2+ exchangers, or Na+-pumps was without effect. These results indicate that CCE plays an important role in the mAChR-mediated release of sAPPalpha.
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Affiliation(s)
- Jin Hyoung Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Ewha Womans University, Seoul, Korea
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27
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Massey L, Mah A, Monteiro M. Ubiquilin regulates presenilin endoproteolysis and modulates gamma-secretase components, Pen-2 and nicastrin. Biochem J 2006; 391:513-25. [PMID: 15975090 PMCID: PMC1276952 DOI: 10.1042/bj20050491] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mutations in presenilin proteins (PS1 and PS2) lead to early-onset Alzheimer's disease. PS proteins are endoproteolytically cleaved into two main fragments: the NTF (PS N-terminal fragment) and the CTF (PS C-terminal fragment). The two fragments are believed to constitute the core catalytic enzyme activity called gamma-secretase, which is responsible for cleaving beta-amyloid precursor protein to release Abeta. Thus, studying factors that modulate PS fragment levels could provide important information about gamma-secretase. Previously, we demonstrated that the protein, ubiquilin-1, interacts both in vivo and in vitro with PS and that overexpression of ubiquilin-1 or -2 leads to increased accumulation of full-length PS proteins. Using wild-type HEK-293 cells (human embryonic kidney 293 cells) and PS-inducible cells, we now show that overexpression of either ubiquilin-1 or -2 decreases the PS NTF and CTF levels. Conversely, siRNA (small interfering RNA)-mediated knockdown of ubiquilin-1 and -2 proteins increased the PS NTF and CTF levels. We considered that ubiquilin might alter PS fragment accumulation by acting as a shuttle factor escorting PS fragments to the proteasome for degradation. However, through proteasome inhibition studies, we show that this does not occur. Instead, our results suggest that ubiquilin regulates PS fragment production. We also examined whether other components of the gamma-secretase complex are affected by ubiquilin expression. Interestingly, overexpression of ubiquilin resulted in a decrease in Pen-2 and nicastrin levels, two essential components of the gamma-secretase complex. In contrast, knockdown of ubiquilin-1 and -2 protein expression by RNAi (RNA interference) increased Pen-2 and nicastrin levels. Finally, we show that inhibition of the proteasome results in decreased PS fragment production and that reversal of proteasome inhibition restores PS fragment production, suggesting that the proteasome may be involved in PS endoproteolysis. These studies implicate ubiquilin as an important factor in regulating PS biogenesis and metabolism.
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Affiliation(s)
- Leann K. Massey
- *Molecular and Cell Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
| | - Alex L. Mah
- *Molecular and Cell Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
| | - Mervyn J. Monteiro
- *Molecular and Cell Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
- †Medical Biotechnology Center, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, U.S.A
- To whom correspondence should be addressed (email )
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28
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Hwang DY, Cho JS, Oh JH, Shim SB, Jee SW, Lee SH, Seo SJ, Lee SK, Lee SH, Kim YK. Differentially expressed genes in transgenic mice carrying human mutant presenilin-2 (N141I): correlation of selenoprotein M with Alzheimer's disease. Neurochem Res 2006; 30:1009-19. [PMID: 16258850 DOI: 10.1007/s11064-005-6787-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2005] [Indexed: 12/31/2022]
Abstract
Mutations in genes for Alzheimer's disease (AD) result in a modulating of gene expressions in the brains of patients with AD. The aim of this study was to identify genes whose expression is modulated due to the over-expression of human mutant presenilin-2 (N141I) (hPS2m) in transgenic mice, which has previously been produced by us. To test this, GeneFishing DEG101 technique was performed on large-scale screen of mRNA from transgenic and non-transgenic brains. A total of 40 transcriptional products corresponding to cDNA were compared between two brains, and 17 showed a differential expression between the samples in all sets of experiments. However, all showed significant homology to known genes. Initially, a cloning corresponding to human selenoprotein M (hSelM) was chosen for investigation further because SelM induced by sodium selenite, a pro-oxidant, may have a functional role in catalyze the free radicals. We found that mouse SelM had significantly suppressed on its transcriptional products in transgenic brains. In parallel, suppression of endogenous was not observed in transgenic brains. Moreover, the levels of green fluorescence on hSelM fusion protein with EGFP were suppressed in the cells transfected with hPS2m, and its levels had actually increased by treatments of sodium selenite. Thus, the results indicate that SelM might play a suppressive or protective role in the pathology of patients with AD and it will be necessary to investigate further on functional roles of other up- and down-regulated gene in future.
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Affiliation(s)
- Dae Y Hwang
- Division of Laboratory Animal Resources, National Institute of Toxicological Research, Korea FDA, 5 Nokbun-dong Eunpyng-ku, 122-704, Seoul, Korea
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29
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Webber KM, Raina AK, Marlatt MW, Zhu X, Prat MI, Morelli L, Casadesus G, Perry G, Smith MA. The cell cycle in Alzheimer disease: a unique target for neuropharmacology. Mech Ageing Dev 2006; 126:1019-25. [PMID: 15936057 DOI: 10.1016/j.mad.2005.03.024] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Revised: 03/21/2005] [Accepted: 03/25/2005] [Indexed: 10/25/2022]
Abstract
Several hypotheses have been proposed attempting to explain the pathogenesis of Alzheimer disease including, among others, theories involving amyloid deposition, tau phosphorylation, oxidative stress, metal ion dysregulation and inflammation. While there is strong evidence suggesting that each one of these proposed mechanisms contributes to disease pathogenesis, none of these mechanisms are able to account for all the physiological changes that occur during the course of the disease. For this reason, we and others have begun the search for a causative factor that predates known features found in Alzheimer disease, and that might therefore be a fundamental initiator of the pathophysiological cascade. We propose that the dysregulation of the cell cycle that occurs in neurons susceptible to degeneration in the hippocampus during Alzheimer disease is a potential causative factor that, together with oxidative stress, would initiate all known pathological events. Neuronal changes supporting alterations in cell cycle control in the etiology of Alzheimer disease include the ectopic expression of markers of the cell cycle, organelle kinesis and cytoskeletal alterations including tau phosphorylation. Such mitotic alterations are not only one of the earliest neuronal abnormalities in the disease, but as discussed herein, are also intimately linked to all of the other pathological hallmarks of Alzheimer disease including tau protein, amyloid beta protein precursor and oxidative stress, and even risk factors such as mutations in the presenilin genes. Therefore, therapeutic interventions targeted toward ameliorating mitotic changes would be predicted to have a profound and positive impact on Alzheimer disease progression.
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Affiliation(s)
- Kate M Webber
- Institute of Pathology, Case Western Reserve University, 2085 Adelbert Road, Cleveland, OH 44106, USA
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30
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Nguyen HN, Hwang DY, Kim YK, Yoon DY, Kim JH, Lee MS, Lee MK, Yun YP, Oh KW, Hong JT. Mutant presenilin 2 increases acetylcholinesterase activity in neuronal cells. Arch Pharm Res 2005; 28:1073-8. [PMID: 16212240 DOI: 10.1007/bf02977404] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A presenilin 2 mutation is believed to be involved in the development of Alzheimer's disease. In addition, transgenic mice with a presenilin 2 mutation have been reported to have learning and memory impairments. In this study, exposing PC12 cells expressing mutant presenilin 2 to 50 microM AP25-35, 30 mM L-glutamate and 50 microM H2O2 caused a significant increase in acetylcholine esterase activity. An in vivo study revealed high levels of this enzyme activity in the mutant presenilin 2 transgenic brains compared with the wild type presenilin 2 transgenic and nontransgenic samples. These results suggest that a mutant presenilin 2-induced neurodegeneration in Alzheimer's disease might be involved in the increase in acetylcholinesterase activity. These findings might help in the development of an appropriate therapeutic intervention targeting mutant presenilin 2-induced Alzheimer's disease.
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Affiliation(s)
- Hong Nga Nguyen
- College of Pharmacy, Chungbuk National University, Cheongju 361-763, Korea
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31
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Nguyen HN, Lee SY, Hwang DY, Kim YK, Yuk DY, Lee JS, Hong JT. Decrease in NF-kappaB, AP-1 and SP-1 activities in neuronal cells expressing presenilin 2. Neuroreport 2005; 16:731-5. [PMID: 15858415 DOI: 10.1097/00001756-200505120-00015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Decreases in activities of the NF-kappaB, AP-1 and SP-1 transcription factors, which could act as antiapoptotic factors, in the presenilin 2 transfected PC12 cells, either in nontreatment conditions or under apoptotic stimulation, were found in this study. Similar results were also found in mice brain cells carrying presenilin 2, especially in the mutant gene expressed ones. These findings suggested that presenilin 2 may be implicated in neuronal cell death by altering the antiapoptotic activity of the transcription factors.
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Affiliation(s)
- Hong Nga Nguyen
- College of Pharmacy, Chungbuk National University, Chungbuk 361-763, Korea
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32
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Wang HQ, Nakaya Y, Du Z, Yamane T, Shirane M, Kudo T, Takeda M, Takebayashi K, Noda Y, Nakayama KI, Nishimura M. Interaction of presenilins with FKBP38 promotes apoptosis by reducing mitochondrial Bcl-2. Hum Mol Genet 2005; 14:1889-902. [PMID: 15905180 DOI: 10.1093/hmg/ddi195] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Presenilins 1 and 2 (PS1/2), causative molecules for familial Alzheimer's disease (FAD), are multipass transmembrane proteins localized predominantly in the endoplasmic reticulum (ER) and Golgi apparatus. Heteromeric protein complexes containing PS1/2 are thought to participate in several functions, including intramembrane proteolysis mediated by their gamma-secretase activities. Previous studies have shown that PS1/2 are also involved in the regulation of apoptotic cell death, although the underlying mechanism remains unknown. Here, we demonstrate that FKBP38, an immunophilin family member residing in the mitochondrial membrane, is an authentic PS1/2-interacting protein. PS1/2 and FKBP38 form macromolecular complexes together with anti-apoptotic Bcl-2. PS1/2 promote the degradation of FKBP38 and Bcl-2 and sequester these proteins in the ER/Golgi compartments, thereby inhibiting FKBP38-mediated mitochondrial targeting of Bcl-2 via a gamma-secretase-independent mechanism. Thus, PS1/2 increase the susceptibility to apoptosis by antagonizing the anti-apoptotic function of FKBP38. In contrast, C-terminal fragments of caspase-processed PS1/2 redistribute Bcl-2 to the mitochondria by abrogating the activity of full-length PS1/2, resulting in a dominant-negative anti-apoptotic effect. In cultured cells and mutant PS1-knockin mice brains, FAD-linked PS1/2 mutants enhance the pro-apoptotic activity by causing a more efficient reduction in mitochondrial Bcl-2 than wild-type PS1/2. These results suggest a novel molecular mechanism for the regulation of mitochondria-mediated apoptosis by competition between PS1/2 and FKBP38 for subcellular targeting of Bcl-2. Excessive pro-apoptotic activity of PS1/2 may play a role in the pathogenesis of FAD.
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Affiliation(s)
- Hua-Qin Wang
- Neurology Unit, Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga, Japan
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33
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Hwang DY, Kim YK, Lim CJ, Cho JS. Mutant nicastrin protein can induce the cytochrome c release and the Bax expression. Int J Neurosci 2004; 114:1277-89. [PMID: 15370186 DOI: 10.1080/00207450490476048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This study investigated whether nicastrin can induce apoptotic cell death in SK-N-MC cells. MTT assays revealed the transfected cells expressing mutant nicastrin, compared with those expressing wild nicastrin or the control vector, showing significantly increased cell death. The mutant nicastrin transfectants were also observed to induce cytosolic cytochrome c release from the mitochondria, and Bax protein expression in response, to increased cell death. These observations suggested that nicastrin, as well as the APP and PS proteins, were also involved in the upregulated Bax mediated neuroblastoma cell death and the release of cytochrome c in the neuroblastoma.
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Affiliation(s)
- Dae Y Hwang
- Division of Laboratory Animal Resources, Korea FDA, National Institute of Toxicological Research, Seoul, Korea.
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34
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Fluhrer R, Friedlein A, Haass C, Walter J. Phosphorylation of Presenilin 1 at the Caspase Recognition Site Regulates Its Proteolytic Processing and the Progression of Apoptosis. J Biol Chem 2004; 279:1585-93. [PMID: 14576165 DOI: 10.1074/jbc.m306653200] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Alzheimer's disease-associated presenilin (PS) 1 is intimately involved in gamma-secretase cleavage of beta-amyloid precursor protein and other proteins. In addition, PS1 plays a role in beta-catenin signaling and in the regulation of apoptosis. Here we demonstrate that phosphorylation of PS1 is regulated by two independent signaling pathways involving protein kinase (PK) A and PKC and that both kinases can directly phosphorylate the large hydrophilic domain of PS1 in vitro and in cultured cells. A phosphorylation site at serine residue 346 was identified that is selectively phosphorylated by PKC but not by PKA. This site is localized within a recognition motif for caspases, and phosphorylation strongly inhibits proteolytic processing of PS1 by caspase activity during apoptosis. Moreover, PS1 phosphorylation reduces the progression of apoptosis. Our data indicate that phosphorylation/dephosphorylation at the caspase recognition site provides a mechanism to reversibly regulate properties of PS1 in apoptosis.
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Affiliation(s)
- Regina Fluhrer
- Department of Neurology, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany
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35
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Abstract
A number of approaches have been taken to recreate and to study the role of genes associated with human neurodegenerative diseases in the model organism Drosophila. These studies encompass the polyglutamine diseases, Parkinson's disease, Alzheimer's disease, and tau-associated pathologies. The findings highlight Drosophila as an important model system in which to study the fundamental pathways influenced by these genes and have led to new insights into aspects of pathogenesis and modifier mechanisms.
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Affiliation(s)
- Nancy M Bonini
- Department of Biology, Howard Hughes Medical Institute, University of Pennsylvania, 415 S. University Avenue, Philadelphia, PA 19104-6018, USA.
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36
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Ling Y, Morgan K, Kalsheker N. Amyloid precursor protein (APP) and the biology of proteolytic processing: relevance to Alzheimer's disease. Int J Biochem Cell Biol 2003; 35:1505-35. [PMID: 12824062 DOI: 10.1016/s1357-2725(03)00133-x] [Citation(s) in RCA: 139] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The processing of amyloid precursor protein (APP) generates amyloid-beta (Abeta) peptides 1-40 and 1-42. The latter is neurotoxic and its accumulation results in amyloid fibril formation and the generation of senile plaques, the hallmark of Alzheimer's disease (AD). Whilst there has been considerable progress made in understanding the generation of Abeta by alpha-, beta- and gamma-secretase activity on APP, recently enzymes involved in the degradation of Abeta have been identified including neprilysin and insulin-degrading enzyme (IDE). We review the pathways involved in proteolytic processing of APP and discuss the potential implications of aberrant proteolysis on neurodegeneration. It is conceivable that single nucleotide polymorphisms (SNPs) in the regulatory regions of genes in these proteolytic cascades, which alter their expression, could contribute to some of the age-related changes seen in AD.
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Affiliation(s)
- Yan Ling
- Division of Clinical Chemistry, Institute of Genetics, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
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37
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Jo DG, Chang JW, Hong HS, Mook-Jung I, Jung YK. Contribution of presenilin/gamma-secretase to calsenilin-mediated apoptosis. Biochem Biophys Res Commun 2003; 305:62-6. [PMID: 12732196 DOI: 10.1016/s0006-291x(03)00688-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mutant presenilins cause early-onset of familial Alzheimer's disease and render cells vulnerable to apoptosis. Calsenilin/DREAM/KChIP3 is a multifunctional calcium-binding protein that interacts with presenilin and mediates calcium-mediated apoptosis. In the present study, we report that the calsenilin-mediated apoptosis is regulated by presenilin. The expression of calsenilin was highly up-regulated in neuronal cells undergoing Abeta42-triggered cell death. The incidence of calsenilin-mediated apoptosis was diminished in presenilin-1(-/-) mouse embryonic fibroblast cells or neuronal cells stably expressing a loss-of-function presenilin-1 mutant. On the contrary, an array of familial Alzheimer's disease-associated presenilin mutants (gain-of-function) increased calsenilin-induced cell death. Moreover, gamma-secretase inhibitors, including compound E and DAPT, decreased the calsenilin-induced cell death. These results suggest that the pro-apoptotic activity of calsenilin coordinates with presenilin/gamma-secretase activity to play a crucial role in the neuronal death of Alzheimer's disease.
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Affiliation(s)
- Dong-Gyu Jo
- Department of Life Science, Kwangju Institute of Science and Technology, Kwangju 500-712, Republic of Korea
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38
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Gamliel A, Teicher C, Hartmann T, Beyreuther K, Stein R. Overexpression of wild-type presenilin 2 or its familial Alzheimer's disease-associated mutant does not induce or increase susceptibility to apoptosis in different cell lines. Neuroscience 2003; 117:19-28. [PMID: 12605888 DOI: 10.1016/s0306-4522(02)00830-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Programmed cell death, or apoptosis, has been implicated in Alzheimer's disease. Mutations in the presenilin (PS) genes, PS1 and PS2, are a major cause of early-onset familial Alzheimer's disease (FAD). Previous studies have suggested that the PS play a role in apoptosis. However, the mechanisms whereby presenilins affect apoptosis and the relationship of FAD-associated presenilin mutants to the apoptotic effect have not been elucidated. In the present study, in an attempt to further explore the effect of PS2 on apoptosis we examined whether overexpression of wild-type or mutant PS2 can directly induce apoptosis or increase cell susceptibility to apoptosis in various cell lines, such as N2a, CHO, and HEK 293T. Wild-type or mutant PS2 was transiently transfected into these cell lines and the viability of the transfected cells was evaluated by their morphology, DNA fragmentation and condensation, appearance of sub-G(1/0) cells, and caspase activation. We also examined the susceptibility of the PS2-transfected cells to apoptosis induced by the apoptotic inducers staurosporine and H(2)O(2). Our results showed that overexpression of either wild type or mutant PS2 in these cell lines did not directly induce apoptosis or increase the susceptibility to apoptosis induced by staurosporine or H(2)O(2). Taken together, these results suggest that overexpression of PS2 does not cause pro-apoptotic effects, at least not in the cellular systems and conditions employed in this study, and therefore it seems unlikely that apoptosis plays a prominent role in the neuropathological effects of PS2 in Alzheimer's disease.
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Affiliation(s)
- A Gamliel
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Israel
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39
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Miroy G, Monteiro MJ. Expression and purification of a convenient Ca2+-calmodulin-dependent protein kinase II GST-fusion substrate. Protein Expr Purif 2002; 26:343-8. [PMID: 12460757 DOI: 10.1016/s1046-5928(02)00557-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Abundant and convenient protein substrates are extremely useful tools for studying protein kinases. However, few such substrates exist for alpha-Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) and those that are available are generally small and expensive peptides that are cumbersome to use. The GST-fusion expression system was used to express a 10 amino acid substrate of CaMKII PLRRTLSVAA in bacteria. Using glutathione-agarose affinity chromatography, we obtained milligram quantities of the highly purified recombinant GST-fusion protein. The GST-fusion protein was tested for its efficacy and specificity as a substrate for CaMKII in phosphorylation assays using recombinant enzyme and radiolabeled [gamma-32P]ATP. The reaction products of these phosphorylation assays were resolved by electrophoresis in SDS-polyacrylamide gels and quantified by phosphoimage analysis. It was found that compared to a phosphorylation-null substrate, GST-PLRRTLAVAA, in which the phosphorylated target serine residue was mutated to an alanine, the GST-PLRRTLSVAA substrate was phosphorylated by CaMKII with an apparent K(m) of 18 microM, indicating that the latter is a highly effective substrate for this enzyme.
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Affiliation(s)
- Greta Miroy
- Medical Biotechnology Center, University of Maryland Biotechnology Institute, Room N352, 725 West Lombard Street, Baltimore, MD 21201, USA
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40
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Wang R, Zhou J, Tang XC. Tacrine attenuates hydrogen peroxide-induced apoptosis by regulating expression of apoptosis-related genes in rat PC12 cells. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2002; 107:1-8. [PMID: 12414117 DOI: 10.1016/s0169-328x(02)00402-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The present studies investigated the effects of tacrine, a selective acetylcholinesterase (AChE) inhibitor and promising anti-dementia agent, on hydrogen peroxide (H(2)O(2))-induced apoptosis and the expression of apoptosis-related genes in rat pheochromocytoma line PC12 cells. Transient exposure of the cells to H(2)O(2) (100 microM) triggered typical apoptosis as evidenced by chromatin condensation, nuclei fragmentation and DNA laddering. RT-PCR studies showed upregulated p53 and bax mRNA levels with H(2)O(2) treatment. The results were further confirmed at protein levels by immunocytochemistry with specific antibodies. Preincubation with tacrine significantly attenuated H(2)O(2)-induced injury, prevented the cells from apoptosis and attenuated H(2)O(2)-induced overexpression of bax and p53. The present findings suggest that tacrine exert significant protection against H(2)O(2)-induced apoptosis possibly through inhibiting expression of pro-apoptosis genes.
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Affiliation(s)
- Rui Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 294 Tai-yuan Road, Shanghai 200031, PR China
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41
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Hwang DY, Chae KR, Kang TS, Hwang JH, Lim CH, Kang HK, Goo JS, Lee MR, Lim HJ, Min SH, Cho JY, Hong JT, Song CW, Paik SG, Cho JS, Kim YK. Alterations in behavior, amyloid beta-42, caspase-3, and Cox-2 in mutant PS2 transgenic mouse model of Alzheimer's disease. FASEB J 2002; 16:805-13. [PMID: 12039862 DOI: 10.1096/fj.01-0732com] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Alzheimer's disease (AD) occurs when neurons in the memory and cognition regions of the brain are accompanied by an accumulation of the long amyloid beta-proteins of the 39 to 43 amino acids derived from the amyloid precursor protein (APP) by cleavage with beta- and gamma-secretase. An increased production of Abeta-42 by mutation of PS2 genes promotes caspase expression and is associated with the Cox-2 found in the brain of AD patients. To address this question in vivo, we expressed the human mutant PS2 (hPS2m) (N141I) as well as wild PS2 (hPS2w) as a control in transgenic (Tg) mice under control of the neuron-specific enolase (NSE) promoter. Water maze tests were used to demonstrate the behavioral defect; dot blot, Western blot, and immunohistochemical analyses were performed on the brain with the hPS2, Abeta-42, caspase-3, and Cox-2 antibody. We concluded that 1) Tg mice showed a behavioral dysfunction in the water maze test, 2) levels of hPS2, Abeta-42, caspase-3, and Cox-2 expression were modulated in the brains of both Tg mice, 3) dense staining with antibody to hPS2, Abeta-42, caspase-3, and Cox-2 was visible in the brains of Tg mice compared with age-matched control mice, and 4) distinguishable AD phenotypes between hPS2w- and hPS2m-Tg mice did not appear. These results suggest that an elevation of Abeta-42 by overexpression of hPS2 and mutation of hPS2m might induce the behavioral deficit and caspase-3 and Cox-2 induction, which could be useful in the therapeutic testing of compounds to have considerable clinical effects.
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Affiliation(s)
- Dae Y Hwang
- Division of Laboratory Animal Resources, Korea FDA, National Institute of Toxicological Research, Seoul 122-704, Korea
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42
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Judge SIV, Yeh JZ, Goolsby JE, Monteiro MJ, Bever CT. Determinants of 4-aminopyridine sensitivity in a human brain kv1.4 k(+) channel: phenylalanine substitutions in leucine heptad repeat region stabilize channel closed state. Mol Pharmacol 2002; 61:913-20. [PMID: 11901231 DOI: 10.1124/mol.61.4.913] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The biophysical and pharmacological effects of individual phenylalanine-for-leucine (Phe-for-Leu) substitutions in the leucine heptad repeat region located at the cytosolic surface of the channel pore, on whole-cell K(+) currents, were studied in cloned and mutated human brain Kvl.4 K(+) channels (hKvl.4) transiently transfected into HeLa cells. Although L2 and L5 are not considered part of the 4-aminopyridine (4-AP) binding site, unlike the L4 heptad leucine, Phe substitutions at L2 (L464) or L5 (L485) increase 4-AP sensitivity by 400-fold, as seen previously in the L4F mutant channel. Greater depolarizing shifts manifest in the voltage dependence of activation and inactivation in L2F (20 mV) and L5F (30 mV) than in L4F (10 mV) relative to hKv1.4. L1F (L457) and L3F (L471) increase 4-AP sensitivity by 8- and 150-fold, respectively, and produce depolarizing shifts in activation of approximately 5 mV without affecting inactivation. The apparent free energy differences of 4-AP binding in each mutant suggest enhanced drug-channel interactions (L2F > or = L4F > or = L5F > L3F > L1F). Deactivation kinetics are accelerated in L2F (11-fold), L5F (8-fold), L1F (5-fold), and L3F (2-fold), at -50 mV. All Phe-for-heptad-Leu substitutions produce gating changes suggesting variable stabilization of the channel closed state conformation, with L1F, L2F, and L5F exhibiting the strongest correlations between altered gating and increased 4-AP sensitivity. If 4-AP blocks the open channel by promoting closure of the activation gate (recent Armstrong-Loboda model), then changes in the leucine heptad repeat that stabilize the channel closed state may contribute to increased 4-AP sensitivity by amplifying the mechanism of 4-AP block.
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Affiliation(s)
- Susan I V Judge
- Research and Neurology Services, VA Maryland Health Care System, Baltimore, Maryland 21201, USA.
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43
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Alves da Costa C, Paitel E, Mattson MP, Amson R, Telerman A, Ancolio K, Checler F, Mattson MP. Wild-type and mutated presenilins 2 trigger p53-dependent apoptosis and down-regulate presenilin 1 expression in HEK293 human cells and in murine neurons. Proc Natl Acad Sci U S A 2002; 99:4043-8. [PMID: 11904448 PMCID: PMC122645 DOI: 10.1073/pnas.062059899] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2001] [Accepted: 02/01/2002] [Indexed: 11/18/2022] Open
Abstract
Presenilins 1 and 2 are two homologous proteins that, when mutated, account for most early onset Alzheimer's disease. Several lines of evidence suggest that, among various functions, presenilins could modulate cell apoptotic responses. Here we establish that the overexpression of presenilin 2 (PS2) and its mutated form Asn-141-Ile-PS2 alters the viability of human embryonic kidney (HEK)293 cells as established by combined trypan blue exclusion, sodium 3'-[1-(phenylamino-carbonyl)-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate assay, and propidium iodide incorporation FACS analyses. The two parent proteins increase the acetyl-DEVD-al-sensitive caspase-3-like activity in both HEK293 cells and Telencephalon specific murine neurons, modulate Bax and bcl-2 expressions, and enhance cytochrome C translocation into the cytosol. We show that overexpression of both wild-type and mutated PS2 increases p53-like immunoreactivity and transcriptional activity. We also establish that wild-type- and mutated PS2-induced caspase activation is reduced by p53 antisense approach and by pifithrin-alpha, a chemical inhibitor of p53. Furthermore, mouse fibroblasts in which the PS2 gene has been knocked out exhibited strongly reduced p53-transcriptional activity. Finally, we establish that the overexpression of both wild-type and mutated PS2 is accompanied by a drastic reduction of endogenous presenilin 1 (PS1) expression. Interestingly, pifithrin-alpha diminished endogenous PS2 immunoreactivity, whereas the inhibitor increases PS1 expression. Altogether, our data demonstrate that wild-type and familial Alzheimer's disease-linked PS2 trigger apoptosis and down-regulate PS1 expression through p53-dependent mechanisms.
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Affiliation(s)
- Cristine Alves da Costa
- Institut de Pharmacologie Moléculaire et Cellulaire of Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6097, Valbonne 06560, France
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44
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Abstract
Ageing is accompanied by a general decline of physiological function, especially at later stages, and significant increases in the incidence of cancer and other degenerative diseases. It has recently been hypothesized that alterations in apoptosis may contribute to these age-associated changes. However, whether there is a role for apoptosis in the ageing process and how ageing may modify the regulatory machinery of apoptosis remains obscure. Although the literature addressing these issues is scarce, research in this area is gaining momentum. Molecules involved in apoptosis signaling in mammals have been found to regulate ageing in organisms such as Caenorhabditis elegans and Drosophila melanogaster. Caloric restriction studies in a wide variety of organisms, ranging from yeast to mammals, suggest the conserved nature of the ageing regulatory systems. It seems very likely that signals that regulate ageing will impact apoptosis and the extent of apoptosis may then impact ageing. However, to date, there has been no direct evidence supporting the existence of such cross-communication between ageing and apoptosis in mammalian system. Here we review progress in the field.
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Affiliation(s)
- Yingpei Zhang
- Department of Cellular and Structural Biology, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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45
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Moise AR, Grant JR, Vitalis TZ, Jefferies WA. Adenovirus E3-6.7K maintains calcium homeostasis and prevents apoptosis and arachidonic acid release. J Virol 2002; 76:1578-87. [PMID: 11799152 PMCID: PMC135875 DOI: 10.1128/jvi.76.4.1578-1587.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
E3-6.7K is a small and hydrophobic membrane glycoprotein encoded by the E3 region of subgroup C adenovirus. Recently, E3-6.7K has been shown to be required for the downregulation of tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) receptors by the adenovirus E3/10.4K and E3/14.5K complex of proteins. We demonstrate here that E3-6.7K has additional protective roles, independent of other virus proteins. In transfected Jurkat T-cell lymphoma cells, E3-6.7K was found to maintain endoplasmic reticulum-Ca(2+) homeostasis and inhibit the induction of apoptosis by thapsigargin. The presence of E3-6.7K also lead to a reduction in the TNF-induced release of arachidonic acid from transfected U937 human histiocytic lymphoma cells. In addition, E3-6.7K protected cells against apoptosis induced through Fas, TNF receptor, and TRAIL receptors. Therefore, E3-6.7K confers a wide range of protective effects against both Ca(2+) flux-induced and death receptor-mediated apoptosis.
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Affiliation(s)
- Alexander R Moise
- Biotechnology Laboratory, Biomedical Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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46
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Bonini NM, Fortini ME. Applications of the Drosophila retina to human disease modeling. Results Probl Cell Differ 2002; 37:257-75. [PMID: 25707079 DOI: 10.1007/978-3-540-45398-7_15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Nancy M Bonini
- Department of Biology, Howard Hughes Medical Institute, University of Pennsylvania, 415 S. University Avenue, Philadelphia, Pennsylvania 19104-6018, USA
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47
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Gamliel A, Teicher C, Michaelson DM, Pradier L, Hartmann T, Beyreuther K, Stein R. Increased expression of presenilin 2 inhibits protein synthesis. Mol Cell Neurosci 2002; 19:111-24. [PMID: 11817902 DOI: 10.1006/mcne.2001.1068] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutations in the presenilin genes PS1 and PS2 are a major cause of early onset familial Alzheimer's disease (AD). Previous studies have suggested that presenilins have several functions, including gamma-secretase activity. It was also shown that presenilin expression is increased in the brains of some AD patients and ischemic rodents. The present study examines the effect of increased presenilin expression on protein synthesis. We show here that overexpression of wild-type PS2 (PS2wt) or PS2 mutant containing the FAD mutation N141I (PS2mut) in various cell lines inhibits the synthesis of coexpressed reporter and endogenous proteins. Furthermore, endogenous PS2 seems to be needed for translation inhibition since PS2 null fibroblasts were translationally more active than PS2(+/+) fibroblasts under conditions known to inhibit translation. Overexpression of PS1 also appeared to cause inhibition of protein synthesis, but its effect was much weaker than that of PS2. Taken together, the results suggest that increased expression of PS2 and possibly also of PS1 inhibits translation and that presenilins may function as regulators of protein synthesis.
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Affiliation(s)
- Amir Gamliel
- Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv, 69978, Israel
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48
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Xiao XQ, Zhang HY, Tang XC. Huperzine A attenuates amyloid beta-peptide fragment 25-35-induced apoptosis in rat cortical neurons via inhibiting reactive oxygen species formation and caspase-3 activation. J Neurosci Res 2002; 67:30-6. [PMID: 11754078 DOI: 10.1002/jnr.10075] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Huperzine A, a novel Lycopodium alkaloid originally discovered in the Chinese herb Qian Ceng Ta (Huperzia serrata), is a reversible, potent, and selective acetylcholinesterase (AChE) inhibitor and has been extensively used for the treatment of Alzheimer's disease (AD) in China. The present studies were designed to investigate effects of huperzine A on amyloid beta-peptide fragment 25-35 (Abeta25-35)-induced neuronal apoptosis and potential mechanisms in primary cultured rat cortical neurons. After exposure of the cells to Abeta25-35 (20 microM), apoptotic cell death was observed as evidenced by a significant decrease in cell viability, alteration of neuronal morphology, and DNA fragmentation. Pretreatment of the cells with huperzine A (0.01-10 microM) prior to Abeta25-35 exposure significantly elevated the cell survival and reduced Abeta25-35-induced nuclei fragmentation. Reactive oxygen species (ROS)-based fluorescence, caspase-3-like fluorogenic cleavage, and Western blot analysis demonstrated that huperzine A reduced Abeta25-35-induced ROS formation in a dose-dependent manner, and 1 microM of huperzine A attenuated Abeta25-35-induced caspase-3 activity at 6, 12, 24, and 48 hr posttreatment. Our results provide the first direct evidence that huperzine A protects neurons against Abeta25-35-induced apoptosis via the inhibition of ROS formation and caspase-3 activity.
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Affiliation(s)
- Xiao Qiu Xiao
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, People's Republic of China
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49
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Araki W, Yuasa K, Takeda S, Takeda K, Shirotani K, Takahashi K, Tabira T. Pro-apoptotic effect of presenilin 2 (PS2) overexpression is associated with down-regulation of Bcl-2 in cultured neurons. J Neurochem 2001; 79:1161-8. [PMID: 11752057 DOI: 10.1046/j.1471-4159.2001.00638.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Presenilin 2 (PS2) is a polytopic membrane protein that is mutated in some cases of familial Alzheimer's disease (AD). The normal functions of PS2 and its pathogenic role in AD remain unclear. We investigated the biological role of this protein in neurons, using adenovirus-mediated transduction of the PS2 gene into rat primary cortical neurons. Immunocytochemical analyses demonstrated increased PS2 immunoreactivity in most neurons infected with recombinant adenoviruses expressing PS2. Neurons infected with wild-type or mutant (N141I) PS2-expressing adenoviruses showed a significant increase in basal cell death, compared with those infected with control beta-galactosidase-expressing adenovirus. Moreover, PS2 overexpression markedly increased neuronal susceptibility to staurosporine-induced apoptosis. Mutant PS2 was more effective in enhancing apoptosis than its wild-type counterpart. Staurosporine-induced death was significantly inhibited by a specific caspase 3 inhibitor. Western analyses revealed that Bcl-2 protein expression was specifically down-regulated in neurons overexpressing PS2, which temporally corresponded to the accumulation of C- and N-terminal fragments of PS2. Additionally, expression of mutant, but not wild-type PS2, increased the production of beta-amyloid protein (Abeta) 42. These data collectively suggest that the pro-apoptotic effect of PS2 is mediated by down-regulation of Bcl-2. PS2 mutations may increase the susceptibility of neurons to apoptotic stimuli by perturbing the regulation of cell death.
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Affiliation(s)
- W Araki
- Division of Demyelinating Disease and Aging, National Institute of Neuroscience, NCNP, Kodaira, Tokyo, Japan.
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Vestling M, Wiehager B, Tanii H, Cowburn RF. Akt activity in presenilin 1 wild-type and mutation transfected human SH-SY5Y neuroblastoma cells after serum deprivation and high glucose stress. J Neurosci Res 2001; 66:448-56. [PMID: 11746362 DOI: 10.1002/jnr.10006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The majority of early-onset familial Alzheimer disease cases are caused by mutations in the genes encoding presenilin 1 (PS1) and presenilin 2 (PS2). Presenilin mutations have been hypothesised to cause Alzheimer disease either by altering amyloid precursor protein metabolism or by increasing the vulnerability of neurons to undergo death by apoptosis. We showed previously that PS1 exon 9 deletion (PS1 DeltaE9) and L250S mutations predispose SH-SY5Y neuroblastoma cells to high glucose stress-induced apoptosis and that the anti-apoptotic effect of insulin-like growth factor I (IGF-I) is compromised by these mutations. The present study investigates whether the susceptibility of PS1 mutation transfected SH-SY5Y cells to undergo apoptosis is likely due to a downregulation of Akt/protein kinase B (Akt), a key intermediate in the phosphatidylinositol 3 (PI3)-kinase arm of the IGF-I signaling pathway. We used two methods to determine the regulation of Akt in response to the pro-apoptotic stimuli of serum deprivation and high glucose stress, as well as treatment with IGF-I. We also looked at the phosphorylatiom state of GSK-3beta at Ser9. Using a kinase assay with immunoprecipitated Akt, we detected an increased Akt activity in PS1 L250S cells at 1 hr after the combination of 20 mM glucose plus 10 nM IGF-I, when compared to the other cell types. This effect, however, was transient in that no mutation related differences were seen at either 6- or 24-hr post-treatment. Immunoblotting for Phospho-Akt as a ratio of total Akt, as well as for GSK-3beta phosphorylated at Ser9 revealed no apparent between cell type and treatment differences. This data strongly indicates that PS1 wt and mutant cells show no major differences in the pattern of Akt regulation after exposure to the pro-apoptotic stimuli of either serum deprivation or high glucose stress, or treatment with IGF-I. It is suggested that another component of IGF-I signaling is likely disrupted in these cells to increase their vulnerability to undergo death by apoptosis.
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Affiliation(s)
- M Vestling
- Karolinska Institutet, NEUROTEC, Division of Experimental Geriatrics, KFC, NOVUM, Huddinge, Sweden
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