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Lotsios NS, Arvanitis N, Charonitakis AG, Mpekoulis G, Frakolaki E, Vassilaki N, Sideris DC, Vassilacopoulou D. Expression of Human L-Dopa Decarboxylase (DDC) under Conditions of Oxidative Stress. Curr Issues Mol Biol 2023; 45:10179-10192. [PMID: 38132481 PMCID: PMC10742706 DOI: 10.3390/cimb45120635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023] Open
Abstract
Oxidative stress is known to influence mRNA levels, translation, and proteolysis. The importance of oxidative stress has been demonstrated in several human diseases, including neurodegenerative disorders. L-Dopa decarboxylase (DDC) is the enzyme that converts L-Dopa to dopamine (DA). In spite of a large number of studies, little is known about the biological significance of the enzyme under physiological and pathological conditions. Here, we investigated the relationship between DDC expression and oxidative stress in human neural and non-neural cells. Oxidative stress was induced by treatment with H2O2. Our data indicated that mRNA and protein expression of DDC was enhanced or remained stable under conditions of ROS induction, despite degradation of total RNA and increased cytotoxicity and apoptosis. Moreover, DDC silencing caused an increase in the H2O2-induced cytotoxicity. The current study suggests that DDC is involved in the mechanisms of oxidative stress.
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Affiliation(s)
- Nikolaos S. Lotsios
- Section of Biochemistry and Molecular Biology, Department of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece; (N.S.L.); (N.A.); (A.G.C.); (D.C.S.)
| | - Nikolaos Arvanitis
- Section of Biochemistry and Molecular Biology, Department of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece; (N.S.L.); (N.A.); (A.G.C.); (D.C.S.)
| | - Alexandros G. Charonitakis
- Section of Biochemistry and Molecular Biology, Department of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece; (N.S.L.); (N.A.); (A.G.C.); (D.C.S.)
| | - George Mpekoulis
- Laboratory of Molecular Virology, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (G.M.); (N.V.)
| | - Efseveia Frakolaki
- Laboratory of Molecular Virology, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (G.M.); (N.V.)
| | - Niki Vassilaki
- Laboratory of Molecular Virology, Hellenic Pasteur Institute (HPI), 11521 Athens, Greece; (G.M.); (N.V.)
| | - Diamantis C. Sideris
- Section of Biochemistry and Molecular Biology, Department of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece; (N.S.L.); (N.A.); (A.G.C.); (D.C.S.)
| | - Dido Vassilacopoulou
- Section of Biochemistry and Molecular Biology, Department of Biology, National and Kapodistrian University of Athens, 15701 Athens, Greece; (N.S.L.); (N.A.); (A.G.C.); (D.C.S.)
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2
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Chalatsa I, Arvanitis N, Arvanitis D, Tsakou AC, Kalantzis ED, Vassiliou AG, Sideris DC, Frakolaki E, Vassilaki N, Vassilacopoulou D. Human L-Dopa decarboxylase interaction with annexin V and expression during apoptosis. Biochimie 2020; 177:78-86. [PMID: 32835737 DOI: 10.1016/j.biochi.2020.08.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/30/2020] [Accepted: 08/17/2020] [Indexed: 01/13/2023]
Abstract
l-Dopa Decarboxylase (DDC) is a pyridoxal requiring enzyme that catalyzes the decarboxylation of L-3,4-dihydroxyphenylalanine (l-Dopa) to Dopamine (DA). The function of DDC in physiological and pathological biochemical pathways remains poorly understood, while the function and regulation of human DDC isoforms is almost completely elusive. We have shown that Annexin V, a fundamental apoptosis marker, is an inhibitor of l-Dopa decarboxylase activity. Here we show the interaction of both the full-length DDC and the truncated isoform alternative DDC (Alt-DDC) with Annexin V in human tissue and cell lines. Interestingly, DDC isoform expression is enhanced or remains unaffected following staurosporine (STS) treatment, despite increased levels of cytotoxicity and apoptosis. The findings presented here provide novel insights concerning the involvement of DDC in programmed cell death.
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Affiliation(s)
- Ioanna Chalatsa
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15701, Athens, Greece; Neurodegenerative Diseases Division, Center for Basic Research, Foundation for Biomedical Research of the Academy of Athens, 4 Soranou Ephessiou Street, 115 27, Athens, Greece
| | - Nikolaos Arvanitis
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15701, Athens, Greece
| | - Dimitrios Arvanitis
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15701, Athens, Greece
| | - Anastasia C Tsakou
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15701, Athens, Greece
| | - Evangelos D Kalantzis
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15701, Athens, Greece
| | - Alice G Vassiliou
- 1st Department of Critical Care Medicine & Pulmonary Services, GP Livanos and M Simou Laboratories, Evangelismos Hospital, Athens Medical School, National & Kapodistrian University of Athens, Athens, Greece
| | - Diamantis C Sideris
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15701, Athens, Greece
| | - Efseveia Frakolaki
- Laboratory of Molecular Virology, Hellenic Pasteur Institute (HPI), Vas. Sofias 127 av, 11521, Athens, Greece
| | - Niki Vassilaki
- Laboratory of Molecular Virology, Hellenic Pasteur Institute (HPI), Vas. Sofias 127 av, 11521, Athens, Greece
| | - Dido Vassilacopoulou
- Department of Biochemistry and Molecular Biology, National and Kapodistrian University of Athens, Panepistimiopolis, 15701, Athens, Greece.
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3
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Canu N, Amadoro G, Triaca V, Latina V, Sposato V, Corsetti V, Severini C, Ciotti MT, Calissano P. The Intersection of NGF/TrkA Signaling and Amyloid Precursor Protein Processing in Alzheimer's Disease Neuropathology. Int J Mol Sci 2017. [PMID: 28632177 PMCID: PMC5486140 DOI: 10.3390/ijms18061319] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Dysfunction of nerve growth factor (NGF) and its high-affinity Tropomyosin receptor kinase A (TrkA) receptor has been suggested to contribute to the selective degeneration of basal forebrain cholinergic neurons (BFCN) associated with the progressive cognitive decline in Alzheimer's disease (AD). The aim of this review is to describe our progress in elucidating the molecular mechanisms underlying the dynamic interplay between NGF/TrkA signaling and amyloid precursor protein (APP) metabolism within the context of AD neuropathology. This is mainly based on the finding that TrkA receptor binding to APP depends on a minimal stretch of ~20 amino acids located in the juxtamembrane/extracellular domain of APP that carries the α- and β-secretase cleavage sites. Here, we provide evidence that: (i) NGF could be one of the “routing” proteins responsible for modulating the metabolism of APP from amyloidogenic towards non-amyloidogenic processing via binding to the TrkA receptor; (ii) the loss of NGF/TrkA signaling could be linked to sporadic AD contributing to the classical hallmarks of the neuropathology, such as synaptic loss, β-amyloid peptide (Aβ) deposition and tau abnormalities. These findings will hopefully help to design therapeutic strategies for AD treatment aimed at preserving cholinergic function and anti-amyloidogenic activity of the physiological NGF/TrkA pathway in the septo-hippocampal system.
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Affiliation(s)
- Nadia Canu
- Department of System Medicine, University of Rome "Tor Vergata", Via Montpellier 1, 00137 Rome, Italy.
- Institute of Cellular Biology and Neurobiology, National Council of Research Rome, Via del Fosso del Fiorano 64, 00143 Rome, Italy.
| | - Giuseppina Amadoro
- Institute of Translational Pharmacology, National Research Council (CNR) Rome, Via Fosso del Cavaliere 100, 00133 Rome, Italy.
| | - Viviana Triaca
- Institute of Cellular Biology and Neurobiology, National Council of Research Rome, Via del Fosso del Fiorano 64, 00143 Rome, Italy.
| | - Valentina Latina
- Institute of Translational Pharmacology, National Research Council (CNR) Rome, Via Fosso del Cavaliere 100, 00133 Rome, Italy.
| | - Valentina Sposato
- European Brain Research Institute Rome, Via del Fosso del Fiorano 64, 00143 Rome, Italy.
| | - Veronica Corsetti
- European Brain Research Institute Rome, Via del Fosso del Fiorano 64, 00143 Rome, Italy.
| | - Cinzia Severini
- Institute of Cellular Biology and Neurobiology, National Council of Research Rome, Via del Fosso del Fiorano 64, 00143 Rome, Italy.
| | - Maria Teresa Ciotti
- Institute of Cellular Biology and Neurobiology, National Council of Research Rome, Via del Fosso del Fiorano 64, 00143 Rome, Italy.
| | - Pietro Calissano
- European Brain Research Institute Rome, Via del Fosso del Fiorano 64, 00143 Rome, Italy.
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4
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Latina V, Caioli S, Zona C, Ciotti MT, Amadoro G, Calissano P. Impaired NGF/TrkA Signaling Causes Early AD-Linked Presynaptic Dysfunction in Cholinergic Primary Neurons. Front Cell Neurosci 2017; 11:68. [PMID: 28360840 PMCID: PMC5350152 DOI: 10.3389/fncel.2017.00068] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 02/24/2017] [Indexed: 12/31/2022] Open
Abstract
Alterations in NGF/TrkA signaling have been suggested to underlie the selective degeneration of the cholinergic basal forebrain neurons occurring in vivo in AD (Counts and Mufson, 2005; Mufson et al., 2008; Niewiadomska et al., 2011) and significant reduction of cognitive decline along with an improvement of cholinergic hypofunction have been found in phase I clinical trial in humans affected from mild AD following therapeutic NGF gene therapy (Tuszynski et al., 2005, 2015). Here, we show that the chronic (10–12 D.I.V.) in vitro treatment with NGF (100 ng/ml) under conditions of low supplementation (0.2%) with the culturing serum-substitute B27 selectively enriches the basal forebrain cholinergic neurons (+36.36%) at the expense of other non-cholinergic, mainly GABAergic (−38.45%) and glutamatergic (−56.25%), populations. By taking advantage of this newly-developed septo-hippocampal neuronal cultures, our biochemical and electrophysiological investigations demonstrate that the early failure in excitatory neurotransmission following NGF withdrawal is paralleled by concomitant and progressive loss in selected presynaptic and vesicles trafficking proteins including synapsin I, SNAP-25 and α-synuclein. This rapid presynaptic dysfunction: (i) precedes the commitment to cell death and is reversible in a time-dependent manner, being suppressed by de novo external administration of NGF within 6 hr from its initial withdrawal; (ii) is specific because it is not accompanied by contextual changes in expression levels of non-synaptic proteins from other subcellular compartments; (ii) is not secondary to axonal degeneration because it is insensible to pharmacological treatment with known microtubule-stabilizing drug such paclitaxel; (iv) involves TrkA-dependent mechanisms because the effects of NGF reapplication are blocked by acute exposure to specific and cell-permeable inhibitor of its high-affinity receptor. Taken together, this study may have important clinical implications in the field of AD neurodegeneration because it: (i) provides new insights on the earliest molecular mechanisms underlying the loss of synaptic/trafficking proteins and, then, of synapes integrity which occurs in vulnerable basal forebrain population at preclinical stages of neuropathology; (ii) offers prime presynaptic-based molecular target to extend the therapeutic time-window of NGF action in the strategy of improving its neuroprotective in vivo intervention in affected patients.
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Affiliation(s)
- Valentina Latina
- Institute of Translational Pharmacology, National Research Council (CNR) Rome, Italy
| | | | - Cristina Zona
- IRCCS Santa Lucia FoundationRome, Italy; Department of Systems Medicine, University of Rome Tor VergataRome, Italy
| | - Maria T Ciotti
- NGF and Molecular Mechanisms of Neurodegenerative Diseases, European Brain Research Institute (EBRI) Rome, Italy
| | - Giuseppina Amadoro
- Institute of Translational Pharmacology, National Research Council (CNR)Rome, Italy; NGF and Molecular Mechanisms of Neurodegenerative Diseases, European Brain Research Institute (EBRI)Rome, Italy
| | - Pietro Calissano
- NGF and Molecular Mechanisms of Neurodegenerative Diseases, European Brain Research Institute (EBRI) Rome, Italy
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Di Loreto S, Falone S, D'Alessandro A, Santini S, Sebastiani P, Cacchio M, Amicarelli F. Regular and moderate exercise initiated in middle age prevents age-related amyloidogenesis and preserves synaptic and neuroprotective signaling in mouse brain cortex. Exp Gerontol 2014; 57:57-65. [PMID: 24835196 DOI: 10.1016/j.exger.2014.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 04/24/2014] [Accepted: 05/05/2014] [Indexed: 12/16/2022]
Abstract
Although the beneficial responses induced in the central nervous system by early-initiated exercise have been broadly investigated, the effects of a chronic and moderate lately-initiated exercise on biochemical hallmarks of very early brain senescence have not been extensively studied. We previously reported that a midlife-initiated regimen of moderate running was able not only to prevent the age-related decay of antioxidative and detoxification functions in mouse brain cortex, but also to preserve neurotrophic support and molecular integrity. On this basis, this work investigated whether and how a 2-mo or 4-mo midlife-initiated running protocol could affect the activity of those systems involved in maintaining neuronal function and in preventing the onset of neurodegeneration within the brain cortex of middle-aged CD-1 mice. In particular, we analyzed the production of the peptide amyloid-β and the expression of synapsin Ia, which is known to play a key role in neurotransmission and synaptic plasticity. In addition, we studied the expression of sirtuin 3, as a protein marker of neuroprotection against age-dependent mitochondrial dysfunction, as well as the pro-death pathway induced by proBDNF through the interaction with p75NTR and the co-receptor sortilin. The midlife-initiated 4-mo running program triggered multiple responses within the mouse brain cortex, through the activation of anti-amyloidogenic, pro-survival, synaptogenic and neuroprotective pathways. However, most of the beneficial actions of the exercise regimen appeared only after 4months, since 2-mo-exercised mice showed marked impairments of the endpoints we considered. This could imply that a midlife-initiated regimen of moderate treadmill running may require an adequate time lag to activate beneficial compensative mechanisms within the mouse brain cortex.
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Affiliation(s)
- Silvia Di Loreto
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Giosuè Carducci, 32 - Rotilio Center, L'Aquila (AQ), Italy
| | - Stefano Falone
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Via Vetoio-Coppito, L'Aquila (AQ), Italy.
| | - Antonella D'Alessandro
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Via Vetoio-Coppito, L'Aquila (AQ), Italy
| | - Silvano Santini
- Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Via Vetoio-Coppito, L'Aquila (AQ), Italy
| | - Pierluigi Sebastiani
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Giosuè Carducci, 32 - Rotilio Center, L'Aquila (AQ), Italy
| | - Marisa Cacchio
- Dept. of Biomedical Sciences, University "G. d'Annunzio", Via dei Vestini, Chieti Scalo (CH), Italy
| | - Fernanda Amicarelli
- Institute of Translational Pharmacology (IFT), National Research Council (CNR), Via Giosuè Carducci, 32 - Rotilio Center, L'Aquila (AQ), Italy; Dept. of Life, Health and Environmental Sciences, University of L'Aquila, Via Vetoio-Coppito, L'Aquila (AQ), Italy
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6
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Wu W, Song W, Li S, Ouyang S, Fok KL, Diao R, Miao S, Chan HC, Wang L. Regulation of apoptosis by Bat3-enhanced YWK-II/APLP2 protein stability. J Cell Sci 2012; 125:4219-29. [PMID: 22641691 DOI: 10.1242/jcs.086553] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
YWK-II protein/APLP2 is a member of an evolutionarily conserved protein family that includes amyloid precursor protein (APP) and amyloid precursor-like protein-1 (APLP1). We have previously demonstrated that YWK-II/APLP2 functions as a novel G(0)-protein-coupled receptor for Müllerian inhibiting substance (MIS) in cell survival. However, factors regulating the stability and turnover of YWK-II/APLP2 have not been identified. Here we present evidence that human leukocyte antigen-B-associated transcript 3 (Bat3), an important regulator involved in apoptosis, can interact with YWK-II/APLP2 and enhance its stability by reducing its ubiquitylation and degradation by the ubiquitin-proteasome system. Coexpression of different Bat3 domain deletion constructs with YWK-II/APLP2 reveals that the proline-rich domain of Bat3 is required for its binding to YWK-II/APLP2. In addition, we find that the protein levels of YWK-II/APLP2 could be enhanced by nuclear export of Bat3 under apoptotic stimulation. We also find elevated levels of Bat3 and YWK-II/APLP2 in human colorectal cancer with a positive correlation between the two. Taken together, these results have revealed a previously undefined mechanism regulating cell apoptosis and suggest that aberrant enhancement of YWK-II/APLP2 by nuclear export of Bat3 may play a role in cancer development by inhibiting cell apoptosis.
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Affiliation(s)
- Wei Wu
- State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, Tsinghua University 5 Dong Dan San Tiao, Beijing 100005, China
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7
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Lu'o'ng KVQ, Nguyên LTH. The beneficial role of vitamin D in Alzheimer's disease. Am J Alzheimers Dis Other Demen 2011; 26:511-20. [PMID: 22202127 PMCID: PMC10845314 DOI: 10.1177/1533317511429321] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2024]
Abstract
Alzheimer's disease (AD) is the most common form of dementia in the elderly individuals and is associated with progressive neurodegeneration of the human neocortex. Patients with AD have a high prevalence of vitamin D deficiency, which is also associated with low mood and impaired cognitive performance in older people. Genetic studies have provided the opportunity to determine which proteins link vitamin D to AD pathology (ie, the major histocompatibility complex class II molecules, vitamin D receptor, renin-angiotensin system, apolipoprotein E, liver X receptor, Sp1 promoter gene, and the poly(ADP-ribose) polymerase-1 gene). Vitamin D also exerts its effect on AD through nongenomic factors, that is, L-type voltage-sensitive calcium channels, nerve growth factor, the prostaglandins, cyclooxygenase 2, reactive oxygen species, and nitric oxide synthase. In conclusion, vitamin D clearly has a beneficial role in AD and improves cognitive function in some patients with AD. Calcitriol, 1 α,25-dihydroxyvitamin D3, is best used for AD because of its active form of vitamin D(3) metabolite and its receptor in the central nervous system.
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8
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Calissano P, Matrone C, Amadoro G. Nerve growth factor as a paradigm of neurotrophins related to Alzheimer's disease. Dev Neurobiol 2010; 70:372-83. [PMID: 20186703 DOI: 10.1002/dneu.20759] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Converging lines of evidence on the possible connection between NGF signaling and Alzheimer's diseases (AD) are unraveling new facets which could depict this neurotrophin (NTF) in a more central role. AD animal models have provided evidence that a shortage of NGF supply may induce an AD-like syndrome. In vitro experiments, moreover, are delineating a possible temporal and causal link between APP amiloydogenic processing and altered post-translational tau modifications. After NGF signaling interruption, the pivotal upstream players of the amyloid cascade (APP, beta-secretase, and active form of gamma-secretase) are up-regulated, leading to an increased production of amyloid beta peptide (Abeta) and to its intracellular aggregation in molecular species of different sizes. Contextually, the Abeta released pool generates an autocrine toxic loop in the same healthy neurons. At the same time tau protein undergoes anomalous, GSKbeta-mediated, phosphorylation at specific pathogenetic sites (Ser262 and Thr 231), caspase(s) and calpain- I- mediated truncation, detachment from microtubules with consequent cytoskeleton collapse and axonal transport impairment. All these events are inhibited when the amyloidogenic processing is reduced by beta and gamma secretase inhibitors or anti-Abeta antibodies and appear to be causally correlated to TrkA, p75CTF, Abeta, and PS1 molecular association in an Abeta-mediated fashion. In this scenario, the so-called trophic action exerted by NGF (and possibly also by other neurotrophins) in these targets neurons is actually the result of an anti-amyloidogenic activity.
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Affiliation(s)
- P Calissano
- Institute of Neurobiology and Molecular Medicine, C.N.R. Fondazione Santa Lucia, Italy.
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Tan DH, Peng SQ, Wu YL, Wang YM, Lu CF, Ding W, Wang QX, Yan CH. Chlorpyrifos Induces Delayed Cytotoxicity after Withdrawal in Primary Hippocampal Neurons through Extracellular Signal-Regulated Kinase Inhibition. Biol Pharm Bull 2009; 32:1649-55. [DOI: 10.1248/bpb.32.1649] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- De-Hong Tan
- Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences
- Department of Pharmacology, College of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University
| | - Shuang-Qing Peng
- Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences
| | - Ying-Liang Wu
- Department of Pharmacology, College of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University
| | - Yi-Mei Wang
- Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences
| | - Chun-Feng Lu
- Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences
- Department of Pharmacology, College of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University
| | - Wei Ding
- Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences
| | - Qiao-Xu Wang
- Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences
| | - Chang-Hui Yan
- Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences
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Harguindey S, Orive G, Cacabelos R, Hevia EM, de Otazu RD, Arranz JL, Anitua E. An integral approach to the etiopathogenesis of human neurodegenerative diseases (HNDDs) and cancer. Possible therapeutic consequences within the frame of the trophic factor withdrawal syndrome (TFWS). Neuropsychiatr Dis Treat 2008; 4:1073-84. [PMID: 19337452 PMCID: PMC2646641 DOI: 10.2147/ndt.s3800] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A novel and integral approach to the understanding of human neurodegenerative diseases (HNDDs) and cancer based upon the disruption of the intracellular dynamics of the hydrogen ion (H(+)) and its physiopathology, is advanced. From an etiopathological perspective, the activity and/or deficiency of different growth factors (GFs) in these pathologies are studied, and their relationships to intracellular acid-base homeostasis reviewed. Growth and trophic factor withdrawal in HNDDs indicate the need to further investigate the potential utilization of certain GFs in the treatment of Alzheimer disease and other neurodegenerative diseases. Platelet abnormalities and the therapeutic potential of platelet-derived growth factors in these pathologies, either through platelet transfusions or other clinical methods, are considered. Finally, the etiopathogenic mechanisms of apoptosis and antiapoptosis in HNDDs and cancer are viewed as opposite biochemical and biological disorders of cellular acid-base balance and their secondary effects on intracellular signaling pathways and aberrant cell metabolism are considered in the light of the both the seminal and most recent data available. The "trophic factor withdrawal syndrome" is described for the first time in English-speaking medical literature, as well as a Darwinian-like interpretation of cellular behavior related to specific and nonspecific aspects of cell biology.
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Affiliation(s)
- Salvador Harguindey
- Institute of Clinical Biology and Metabolism, c/o Postas 13, 01004 Vitoria, Spain.
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11
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Yin X, Ouyang S, Xu W, Zhang X, Fok KL, Wong HY, Zhang J, Qiu X, Miao S, Chan HC, Wang L. YWK-II protein as a novel Go-coupled receptor for Müllerian inhibiting substance in cell survival. J Cell Sci 2007; 120:1521-8. [PMID: 17452623 DOI: 10.1242/jcs.001230] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Müllerian inhibiting substance (MIS) has recently been implicated in multiple cellular functions including promotion of cell survival, but the receptor(s) and signaling pathways involved remain elusive. We have investigated the possibility of YWK-II protein, previously shown to interact physically with MIS and Go protein, being a receptor mediating the cell survival effect of MIS. In YWK-II-overexpressing CHO cells, MIS activates the Go-coupled ERK1/2 signaling pathway and promotes cell survival with altered levels of p53 and caspase-3. YWK-II antibody is found to interfere with the ability of MIS to promote viability of mouse sperm and affect MIS-activated ERK1/2 phosphorylation. In vivo studies involving injection of YWK-II antibody into the seminiferous tubule of the mouse testis, where MIS is known to be produced, show significant reduction in the sperm count with accumulation of p53 and cleaved caspase-3 in testicular nuclei. Taken together, the present study has demonstrated a new Go-coupled receptor for MIS in mediating ERK1/2 activation leading to anti-apoptotic activity or cell survival.
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MESH Headings
- Amyloid beta-Protein Precursor/genetics
- Amyloid beta-Protein Precursor/metabolism
- Amyloid beta-Protein Precursor/physiology
- Animals
- Anti-Mullerian Hormone
- Apoptosis/drug effects
- Apoptosis/physiology
- CHO Cells
- COS Cells
- Caspase 3/metabolism
- Cell Survival/drug effects
- Chlorocebus aethiops
- Cricetinae
- Cricetulus
- Extracellular Signal-Regulated MAP Kinases/metabolism
- GTP-Binding Protein alpha Subunits, Gi-Go/antagonists & inhibitors
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- Glycoproteins/pharmacology
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Humans
- Male
- Mice
- Mice, Inbred BALB C
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Nerve Tissue Proteins/physiology
- Phosphorylation/drug effects
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Receptors, G-Protein-Coupled/physiology
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Receptors, Peptide/physiology
- Receptors, Transforming Growth Factor beta
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/metabolism
- Spermatozoa/cytology
- Spermatozoa/drug effects
- Testicular Hormones/pharmacology
- Testis/cytology
- Testis/drug effects
- Testis/metabolism
- Transfection
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Affiliation(s)
- Xueqian Yin
- National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China
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12
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Schliebs R, Arendt T. The significance of the cholinergic system in the brain during aging and in Alzheimer's disease. J Neural Transm (Vienna) 2006; 113:1625-44. [PMID: 17039298 DOI: 10.1007/s00702-006-0579-2] [Citation(s) in RCA: 374] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 09/27/2006] [Indexed: 12/11/2022]
Abstract
Acetylcholine is widely distributed in the nervous system and has been implicated to play a critical role in cerebral cortical development, cortical activity, controlling cerebral blood flow and sleep-wake cycle as well as in modulating cognitive performances and learning and memory processes. Cholinergic neurons of the basal forebrain complex have been described to undergo moderate degenerative changes during aging, resulting in cholinergic hypofunction that has been related to the progressing memory deficits with aging. Basal forebrain cholinergic cell loss is also a consistent feature of Alzheimer's disease, which has been suggested to cause, at least partly, the cognitive deficits observed, and has led to the formulation of the cholinergic hypotheses of geriatric memory dysfunction. Impaired cortical cholinergic neurotransmission may also contribute to beta-amyloid plaque pathology and increase phosphorylation of tau protein the main component of neurofibrillar tangles in Alzheimer's disease. Understanding the molecular mechanisms underlying the interrelationship between cortical cholinergic dysfunction, beta-amyloid formation and deposition, and tau pathology in Alzheimer's disease, would allow to derive potential treatment strategies to pharmacologically intervene in the disease-causing signaling cascade.
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Affiliation(s)
- R Schliebs
- Department of Neurochemistry, Paul Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany.
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Schliebs R. Basal forebrain cholinergic dysfunction in Alzheimer's disease--interrelationship with beta-amyloid, inflammation and neurotrophin signaling. Neurochem Res 2006; 30:895-908. [PMID: 16187224 DOI: 10.1007/s11064-005-6962-9] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2005] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease, the most common neurodegenerative disorder of senile dementia, is characterized by two major morpho-pathological hallmarks. Deposition of extracellular neuritic, beta-amyloid peptide-containing plaques (senile plaques) in cerebral cortical regions of Alzheimer patients is accompanied by the presence of intracellular neurofibrillary tangles in cerebral pyramidal neurons. Basal forebrain cholinergic dysfunction is also a consistent feature of Alzheimer's disease, which has been suggested to cause, at least partly, the cognitive deficits observed in patients with Alzheimer's disease. Impaired cortical cholinergic neurotransmission may also contribute to beta-amyloid plaque pathology in Alzheimer's disease by affecting expression and processing of the beta-amyloid precursor protein (APP). Vice versa, low level of soluble beta-amyloid has been observed to inhibit cholinergic synaptic function. Deposition of beta-amyloid plaques in Alzheimer's disease is also accompanied by a significant plaque-associated glial up-regulation of interleukin-1, which has been attributed to affect expression and metabolism of APP and to interfere with cholinergic transmission. Understanding the molecular mechanisms underlying the interrelationship between cortical cholinergic dysfunction, beta-amyloid formation and deposition, as well as local inflammatory upregulation, would allow to derive potential treatment strategies to pharmacologically intervene in the disease-causing signaling cascade.
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Affiliation(s)
- Reinhard Schliebs
- Paul Flechsig Institute for Brain Research, Department of Neurochemistry, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany.
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14
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Makarenko AN, Vasil'eva IG, Chopik NG, Galanta ES, Tsyubko OI, Oleksenko NP. Effect of Active Fraction of Cerebral on Expression of Caspase-3 and β-Amyloid Precursor Protein during Therapy of Hemorrhagic Stroke in the Acute and Delayed Periods. Bull Exp Biol Med 2005; 139:207-9. [PMID: 16027808 DOI: 10.1007/s10517-005-0249-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Active anti-stroke fraction of Cerebral preparation (extract of water-soluble molecules from brain tissue of animals with hemorrhagic stroke) decreased caspase-3 expression and improved survival of experimental animals in the acute period after hemorrhagic stroke.
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Affiliation(s)
- A N Makarenko
- Institute of Pharmacology and Toxicology, Ukrainian Academy of Sciences, Kiev
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15
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Nishimura I, Takazaki R, Kuwako KI, Enokido Y, Yoshikawa K. Upregulation and antiapoptotic role of endogenous Alzheimer amyloid precursor protein in dorsal root ganglion neurons. Exp Cell Res 2003; 286:241-51. [PMID: 12749853 DOI: 10.1016/s0014-4827(03)00066-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The amyloid precursor protein (APP) is a transmembrane protein whose abnormal processing is associated with the pathogenesis of Alzheimer's disease. In this study, we examined the expression and role of cell-associated APP in primary dorsal root ganglion (DRG) neurons. When dissociated DRG cells prepared from mouse embryos were treated with nerve growth factor (NGF), neuronal APP levels were transiently elevated. DRG neurons treated with an antibody against cell surface APP failed to mature and underwent apoptosis. When NGF was withdrawn from the cultures after a 36-h NGF treatment, virtually all neurons underwent apoptosis by 48 h. During the course of apoptosis, some neurons with intact morphology contained increased levels of APP immunoreactivity, whereas the APP levels were greatly reduced in apoptotic neurons. Furthermore, affected neurons contained immunoreactivities for activated caspase-3, a caspase-cleaved APP fragment (APPDeltaC31), and Abeta. Downregulation of endogenous APP expression by treatment with an APP antisense oligodeoxynucleotide significantly increased the number of apoptotic neurons in NGF-deprived DRG cultures. Furthermore, overexpression of APP by adenovirus vector-mediated gene transfer reduced the number of apoptotic neurons deprived of NGF. These results suggest that endogenous APP is upregulated to exert an antiapoptotic effect on neurotrophin-deprived DRG neurons and subsequently undergoes caspase-dependent proteolysis.
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Affiliation(s)
- Isao Nishimura
- Division of Regulation of Macromolecular Functions, Osaka University, Yamadaoka 3-2, Suita, Osaka 565-0871, Japan
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16
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Kashour T, Burton T, Dibrov A, Amara FM. Late Simian virus 40 transcription factor is a target of the phosphoinositide 3-kinase/Akt pathway in anti-apoptotic Alzheimer's amyloid precursor protein signalling. Biochem J 2003; 370:1063-75. [PMID: 12472467 PMCID: PMC1223229 DOI: 10.1042/bj20021197] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2002] [Revised: 12/02/2002] [Accepted: 12/10/2002] [Indexed: 12/11/2022]
Abstract
The association of familial Alzheimer's disease (FAD) with mutations in Alzheimer's amyloid precursor protein (APP) suggests important functions for APP in the central nervous system. Mutations in APP impair its function to confer resistance to apoptosis in cells under stress, and this may contribute to neurodegeneration in Alzheimer's disease (AD) brain, but the mechanisms involved are unknown. We examined the role of the late Simian virus 40 transcription factor (LSF), in anti-apoptotic APP pathways. We show that in APP-deficient B103 cells, expression of wild-type human APP (hAPPwt), but not of FAD-mutant APP, inhibited staurosporine (STS)-induced apoptosis. This inhibition was further enhanced by expression of LSFwt, although LSFwt alone was not sufficient to inhibit STS-induced apoptosis. In contrast, expression of dominant-negative LSF led to a marked increase in STS-induced cell death that was significantly blocked by hAPPwt. These effects of APP were accompanied by LSF nuclear translocation and dependent gene transcription. The activation of LSF is dependent on the expression of hAPPwt and is inhibited by the expression of dominant-negative forms of either phosphoinositide 3-kinase or Akt. These results demonstrate that LSF activation is required for the neuroprotective effects of APP via phosphoinositide 3-kinase/Akt signalling. Alterations in this pathway by aberrations in APP and/or LSF could promote neuronal loss in AD brain, due to secondary insults. Thus a link is established between APP and LSF and AD.
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Affiliation(s)
- Tarek Kashour
- Section of Cardiology, Department of Medicine, St. Boniface General Hospital, The University of Manitoba, 770 Bannatyne Avenue, Winnipeg, MB, Canada R3E 0W3
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17
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Seo H, Ferree AW, Isacson O. Cortico-hippocampal APP and NGF levels are dynamically altered by cholinergic muscarinic antagonist or M1 agonist treatment in normal mice. Eur J Neurosci 2002; 15:498-506. [PMID: 11876777 DOI: 10.1046/j.0953-816x.2001.01884.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
To determine whether altered cholinergic neurotransmission can modify the long-term secretion of amyloid precursor protein (APP), endogenous levels of APP and nerve growth factor (NGF), we administered a selective M1 muscarinic receptor agonist (RS86) or the muscarinic antagonist, atropine, for 7 days in vivo into young adult mice (C57BL/6j). The levels of NGF and total APP in the hippocampus, frontal cortex, striatum, parietal cortex and cerebrospinal fluid (CSF) were examined by ELISA and Western blot. We found that this repeated i.m. administration of M1 receptor agonist resulted in decreased total APP levels in the hippocampus, frontal cortex and parietal cortex, and increased secreted alpha-APPs levels in the CSF. M1 agonist treatment also resulted in decreased NGF levels in the hippocampus and CSF. These effects of the M1 muscarinic agonist could be blocked by atropine, which by itself elevated tissue levels of total APP. Interestingly, we found that the decrease of total APP in the hippocampus and striatum after M1 agonist treatment inversely correlated with the change in NGF levels. These data suggest that a sustained increased cholinergic, M1-mediated neurotransmission will enhance secretion of alpha-APPs in CSF and adaptively reduce the levels of total APP and NGF in the corticohippocampal regions of normal mice. The dynamic and adaptive regulation linking total APP and NGF levels in normal adult mice is relevant for understanding the pathophysiology of conditions with cholinergic and APP related pathologies, like Alzheimer's disease and Down's syndrome.
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Affiliation(s)
- Hyemyung Seo
- Neuroregeneration Laboratories, Harvard Medical School, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA
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18
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Abstract
The amyloid precursor protein (APP) gene and its protein products have multiple functions in the central nervous system and fulfil criteria as neuractive peptides: presence, release and identity of action. There is increased understanding of the role of secretases (proteases) in the metabolism of APP and the production of its peptide fragments. The APP gene and its products have physiological roles in synaptic action, development of the brain, and in the response to stress and injury. These functions reveal the strategic importance of APP in the workings of the brain and point to its evolutionary significance.
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Affiliation(s)
- P K Panegyres
- Department of Neuropathology, Royal Perth Hospital, Western Australia.
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Heininger K. A unifying hypothesis of Alzheimer's disease. IV. Causation and sequence of events. Rev Neurosci 2001; 11 Spec No:213-328. [PMID: 11065271 DOI: 10.1515/revneuro.2000.11.s1.213] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Contrary to common concepts, the brain in Alzheimer's disease (AD) does not follow a suicide but a rescue program. Widely shared features of metabolism in starvation, hibernation and various conditions of energy deprivation, e.g. ischemia, allow the definition of a deprivation syndrome which is a phylogenetically conserved adaptive response to energetic stress. It is characterized by hypometabolism, oxidative stress and adjustments of the glucose-fatty acid cycle. Cumulative evidence suggests that the brain in aging and AD actively adapts to the progressive fuel deprivation. The counterregulatory mechanisms aim to preserve glucose for anabolic needs and promote the oxidative utilization of ketone bodies. The agent mediating the metabolic switch is soluble Abeta which inhibits glucose utilization and stimulates ketone body utilization at various levels. These processes, which are initiated during normal aging, include inhibition of pro-glycolytic neurohormones, cholinergic transmission, and pyruvate dehydrogenase, the key transmitter and effector systems regulating glucose metabolism. Hormonal and effector systems which promote ketone body utilization, such as glucocorticosteroid and galanin activity, GABAergic transmission, nitric oxide, lipid transport, Ca2+ elevation, and ketone body metabolizing enzymes, are enhanced. A multitude of risk factors feed into this pathophysiological cascade at a variety of levels. Taking into account its pleiotropic regulatory actions in the deprivation response, a new name for Abeta is suggested: deprivin. On the other hand, cumulative evidence, taken together compelling, suggests that senile plaques are the dump rather than the driving force of AD. Moreover, the neurotoxic action of fibrillar Abeta is a likely in vitro artifact but does not contribute significantly to the in vivo pathophysiological events. This archaic program, conserved from bacteria to man, aims to ensure the survival of a deprived organism and controls such divergent processes as sporulation, hibernation, aging and aging-related diseases. In contrast to the immature brain, ketone body utilization of the aged brain is no longer sufficient to meet the energetic demands and is later supplemented by lactate, thus recapitulating in reverse order the sequential fuel utilization of the immature brain. The transduction pathways which operate to switch metabolism also convey the programming and balancing of the de-/redifferentiation/apoptosis cell cycle decisions. This encompasses the reiteration of developmental processes such as transcription factor activation, tau hyperphosphorylation, and establishment of growth factor independence by means of Ca2+ set point shift. Thus, the increasing energetic insufficiency results in the progressive centralization of metabolic activity to the neuronal soma, leading to pruning of the axonal/dendritic trees, loss of neuronal polarity, downregulation of neuronal plasticity and, eventually, depending on the Ca2+ -energy-redox homeostasis, degeneration of vulnerable neurons. Finally, it is outlined that genetic (e.g. Down's syndrome, APP and presenilin mutations and apoE4) and environmental risk factors represent progeroid factors which accelerate the aging process and precipitate the manifestation of AD as a progeroid systemic disease. Aging and AD are related to each other by threshold phenomena, corresponding to stage 2, the stage of resistance, and stage 3, exhaustion, of a metabolic stress response.
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Affiliation(s)
- K Heininger
- Department of Neurology, Heinrich Heine University, Düsseldorf, Germany
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Sennvik K, Benedikz E, Fastbom J, Sundström E, Winblad B, Ankarcrona M. Calcium ionophore A23187 specifically decreases the secretion of beta-secretase cleaved amyloid precursor protein during apoptosis in primary rat cortical cultures. J Neurosci Res 2001; 63:429-37. [PMID: 11223918 DOI: 10.1002/1097-4547(20010301)63:5<429::aid-jnr1038>3.0.co;2-u] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Alzheimer's disease (AD) is characterized by the degeneration and loss of neurons, intracellular neurofibrillary tangles and the accumulation of extracellular senile plaques consisting mainly of beta-amyloid (A beta). A beta is generated from the amyloid precursor protein (APP) by sequential beta- and gamma-secretase cleavage. Alternatively, APP may be cleaved within the A beta region by alpha-secretase, preventing A beta formation. Here we investigated APP processing and secretion in primary neurons, using either colchicine or the calcium ionophore A23187 to induce apoptosis. Cell viability was determined by MTT measurements and apoptosis was further confirmed by annexin V and propidium iodide staining. We found that exposure to A23187 significantly decreased the secretion of soluble beta-secretase cleaved APP (beta-sAPP) in a caspase-dependent manner, although the secretion of total soluble APP beta sAPP) did not change. In addition, caspase inhibition restored cell viability to control levels. Exposure to colchicine did not change the amount of either secreted beta-sAPP or total sAPP and caspase inhibition was only partially able to restore cell viability. We conclude that calcium homeostasis is an important apoptotic effector specifically affecting the beta-secretase cleavage of APP.
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Affiliation(s)
- K Sennvik
- Karolinska Institutet, NEUROTEC, Division of Geriatric Medicine, KFC NOVUM, Huddinge, Sweden.
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21
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Lahiri DK, Song1 W, Ge YW. Analysis of the 5'-flanking region of the beta-amyloid precursor protein gene that contributes to increased promoter activity in differentiated neuronal cells. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2000; 77:185-98. [PMID: 10837914 DOI: 10.1016/s0169-328x(00)00051-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
To study the transcription control of the beta-amyloid precursor protein (betaAPP) in Alzheimer's disease (AD), we functionally characterized the betaAPP gene promoter in differentiated cells. PC12 cells were first differentiated with nerve growth factor (NGF) and then transient transfection analysis was done with a series of 5'-deletion constructs, that extended as far upstream as -7900 down to +104 base pair (bp) relative to the transcription start site (+1). The truncated regions of the promoter were linked upstream to a reporter gene, chloramphenicol acetyl transferase (CAT). The CAT assay was performed to compare promoter activity of different 5'-flanking and intronic regions of the betaAPP gene. Our results suggest that the longest (-7900/+104) and one of the shortest (-47/+104) regions possessed significantly higher levels of promoter activity than the promoterless vector in NGF-differentiated PC12 cells. A deletion of about 7600 bp region from the -7900 to +104 construct resulted in 50% loss of original promoter activity. A deletion of all but 47 bp from the -7900 to +104 construct resulted in the loss of 66% (and retention of 34%) promoter activity. The region -3416/+104 bp displayed the strongest promoter activity whereas +1/+104 bp showed the least activity among all deletion constructs studied. The upstream region -5529 to -3416 contains a negative regulatory element and -3416 to -1131 contains a positive regulatory element. The very upstream region, -7900 to -3411, lacks independent functional activity. The 5'-UTR region (+1 to +104) showed minimum activity and the -75 to +104 region constitutes the basic promoter element. The first exon or a large part of the first intron (+99 to +6200) did not display any significant promoter activity. Thus, several positive and negative regulatory elements influence the basal level of betaAPP promoter activity in NGF-differentiated PC12 cells. We speculate that any structural alteration(s) due to a specific mutation in these regulatory regions can potentially alter the transcriptional machinery, and that can perhaps affect the level of beta-amyloid protein involved in AD.
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Affiliation(s)
- D K Lahiri
- Laboratory of Molecular Neurogenetics, Institute of Psychiatric Research, Department of Psychiatry, 791 Union Drive, Room No.: Pr-313, Indiana University School of Medicine, Indianapolis, IN 46202-4887, USA.
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