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Yenki P, Khodagholi F, Shaerzadeh F. Inhibition of phosphorylation of JNK suppresses Aβ-induced ER stress and upregulates prosurvival mitochondrial proteins in rat hippocampus. J Mol Neurosci 2012; 49:262-9. [PMID: 22706709 DOI: 10.1007/s12031-012-9837-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 06/06/2012] [Indexed: 12/27/2022]
Abstract
A growing body of evidence indicates that c-Jun N-terminal kinases (JNKs) is activated in Alzheimer's disease. Herein, we examine the effect of the JNK specific inhibitor, SP600125, on the level of functional proteins or transcription factors related to endoplasmic reticulum (ER) and oxidative stress induced by amyloid beta (Aβ). Our results clearly showed the ability of SP600125 to decrease the levels of caspase 12 and calpain 2, two important enzymes involved in ER stress. Aβ has been suggested to be able to decrease the phosphorylation level of cAMP response element-binding (CREB) through mitogen-activated protein kinase pathway. We observed that JNK inhibition in Aβ-injected rats can restore the activation of CREB through increasing its phosphorylation level. This effect may explain the increase observed in c-fos level, as a CREB downstream factor under JNK inhibition in Aβ-injected rats. Following Aβ injection, the levels of pro-survival mitochondrial proteins including nuclear respiratory factor-1 (NRF-1), peroxisome proliferator-activated receptor gamma co-activator 1-alpha, and mitochondrial transcription factor A (TFAM) significantly decreased, which could be returned to control level with JNK inhibition. We suggest that the elevation in the level of PGC1-alpha and other mitochondrial proteins is the result of an increase in CREB activation as the upstream factor of PGC1-alpha. Also, we observed that pretreatment with SP600125 leads to a greater increase of nuclear related factor-2 (Nrf2) level compared with the Aβ-injected group. Nrf2 has been shown to bind to CREB-binding factor leading to their contribution in Nrf2 target genes expression. Besides, NRF-1 and TFAM are reported as Nrf2 targets. Based on our data, we can conclude that JNK carry out partial destructive effects of Aβ in rat brain.
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Affiliation(s)
- Parvin Yenki
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Cigarette smoking accelerated brain aging and induced pre-Alzheimer-like neuropathology in rats. PLoS One 2012; 7:e36752. [PMID: 22606286 PMCID: PMC3350465 DOI: 10.1371/journal.pone.0036752] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 04/12/2012] [Indexed: 12/21/2022] Open
Abstract
Cigarette smoking has been proposed as a major risk factor for aging-related pathological changes and Alzheimer's disease (AD). To date, little is known for how smoking can predispose our brains to dementia or cognitive impairment. This study aimed to investigate the cigarette smoke-induced pathological changes in brains. Male Sprague-Dawley (SD) rats were exposed to either sham air or 4% cigarette smoke 1 hour per day for 8 weeks in a ventilated smoking chamber to mimic the situation of chronic passive smoking. We found that the levels of oxidative stress were significantly increased in the hippocampus of the smoking group. Smoking also affected the synapse through reducing the expression of pre-synaptic proteins including synaptophysin and synapsin-1, while there were no changes in the expression of postsynaptic protein PSD95. Decreased levels of acetylated-tubulin and increased levels of phosphorylated-tau at 231, 205 and 404 epitopes were also observed in the hippocampus of the smoking rats. These results suggested that axonal transport machinery might be impaired, and the stability of cytoskeleton might be affected by smoking. Moreover, smoking affected amyloid precursor protein (APP) processing by increasing the production of sAPPβ and accumulation of β–amyloid peptide in the CA3 and dentate gyrus region. In summary, our data suggested that chronic cigarette smoking could induce synaptic changes and other neuropathological alterations. These changes might serve as evidence of early phases of neurodegeneration and may explain why smoking can predispose brains to AD and dementia.
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Guix FX, Wahle T, Vennekens K, Snellinx A, Chávez-Gutiérrez L, Ill-Raga G, Ramos-Fernandez E, Guardia-Laguarta C, Lleó A, Arimon M, Berezovska O, Muñoz FJ, Dotti CG, De Strooper B. Modification of γ-secretase by nitrosative stress links neuronal ageing to sporadic Alzheimer's disease. EMBO Mol Med 2012; 4:660-73. [PMID: 22488900 PMCID: PMC3402223 DOI: 10.1002/emmm.201200243] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 03/30/2012] [Accepted: 03/30/2012] [Indexed: 11/26/2022] Open
Abstract
Inherited familial Alzheimer's disease (AD) is characterized by small increases in the ratio of Aβ42 versus Aβ40 peptide which is thought to drive the amyloid plaque formation in the brain of these patients. Little is known however whether ageing, the major risk factor for sporadic AD, affects amyloid beta-peptide (Aβ) generation as well. Here we demonstrate that the secretion of Aβ is enhanced in an in vitro model of neuronal ageing, correlating with an increase in γ-secretase complex formation. Moreover we found that peroxynitrite (ONOO−), produced by the reaction of superoxide anion with nitric oxide, promoted the nitrotyrosination of presenilin 1 (PS1), the catalytic subunit of γ-secretase. This was associated with an increased association of the two PS1 fragments, PS1-CTF and PS1-NTF, which constitute the active catalytic centre. Furthermore, we found that peroxynitrite shifted the production of Aβ towards Aβ42 and increased the Aβ42/Aβ40 ratio. Our work identifies nitrosative stress as a potential mechanistic link between ageing and AD.
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Soluble amyloid precursor protein-α modulates β-secretase activity and amyloid-β generation. Nat Commun 2012; 3:777. [PMID: 22491325 DOI: 10.1038/ncomms1781] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 03/08/2012] [Indexed: 01/02/2023] Open
Abstract
In sporadic age-related forms of Alzheimer's disease (AD), it is unclear why amyloid-β (Aβ) peptides accumulate. Here we show that soluble amyloid precursor protein-α (sAPP-α) decreases Aβ generation by directly associating with β-site APP-converting enzyme (BACE)1, thereby modulating APP processing. Whereas specifically targeting sAPP-α using antibodies enhances Aβ production; in transgenic mice with AD-like pathology, sAPP-α overexpression decreases β-amyloid plaques and soluble Aβ. In support, immunoneutralization of sAPP-α increases APP amyloidogenic processing in these mice. Given our current findings, and because a number of risk factors for sporadic AD serve to lower levels of sAPP-α in brains of AD patients, inadequate sAPP-α levels may be sufficient to polarize APP processing towards the amyloidogenic, Aβ-producing route. Therefore, restoration of sAPP-α or enhancement of its association with BACE may be viable strategies to ameliorate imbalances in APP processing that can lead to AD pathogenesis.
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Ehrlich D, Hochstrasser T, Humpel C. Effects of oxidative stress on amyloid precursor protein processing in rat and human platelets. Platelets 2012; 24:26-36. [PMID: 22385218 DOI: 10.3109/09537104.2012.661104] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Alzheimer's disease (AD) is the most common neurodegenerative illness affecting the elderly and is characterized by beta-amyloid (Aβ) deposition in the brain (plaques) and in microvessels (Aβ-angiopathy). The reasons for Aβ deposition are not clear, but an impaired clearance of Aβ at the blood-brain barrier may be implicated and oxidative stress possibly plays a major role in this process. Platelets are of particular interest, because they contain high levels of the amyloid precursor protein (APP) and in AD an abnormal expression of platelets APP fragments was found. The aim of the present study was to investigate (1) if oxidative stress induced by hydrogen peroxide (H(2)O(2)) affects APP expression in rat and human platelets and (2) to compare the APP changes with platelets of AD patients. In rat platelets, all three fragments of APP (130-110-106 kilo Dalton, kDa) were found. H(2)O(2) (10 mM, 20 minutes) significantly reduced all three fragments in rat platelets, did not affect CD62P-staining and slightly increased the size of actin as seen in the Western blot. The effect was not seen at 1 mM H(2)O(2) and was counteracted by glutathione. Immunohistochemistry for CD62P, CD61, APP and Annexin-V was used to verify the changes at the cellular level. In platelets of young volunteers (age = 33 ± 4 years), 10 mM H(2)O(2) markedly reduced the smaller APP 110 and 106 kDa fragments after 20 minutes. Our data show that platelets of AD patients (age = 80 ± 1 years) had a significant reduced 130 kDa fragment compared to controls (age = 70 ± 2 years). In summary, oxidative stress may account for a dysfunctional processing of APP in rat and human control platelets and possibly in AD patients.
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Affiliation(s)
- Daniela Ehrlich
- Laboratory of Psychiatry and Exp. Alzheimers Research, Department of Psychiatry and Psychotherapy, Innsbruck Medical University, Innsbruck, Austria
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Mouton-Liger F, Paquet C, Dumurgier J, Bouras C, Pradier L, Gray F, Hugon J. Oxidative stress increases BACE1 protein levels through activation of the PKR-eIF2α pathway. Biochim Biophys Acta Mol Basis Dis 2012; 1822:885-96. [PMID: 22306812 DOI: 10.1016/j.bbadis.2012.01.009] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 01/18/2012] [Accepted: 01/18/2012] [Indexed: 12/14/2022]
Abstract
Beta-site APP cleaving enzyme 1 (BACE1) is the rate limiting enzyme for accumulation of amyloid β (Aβ)-peptide in the brain in Alzheimer's disease (AD). Oxidative stress (OS) that leads to metabolic dysfunction and apoptosis of neurons in AD enhances BACE1 expression and activity. The activation of c-jun N-terminal kinase (JNK) pathway was proposed to explain the BACE1 mRNA increase under OS. However, little is known about the translational control of BACE1 in OS. Recently, a post-transcriptional increase of BACE1 level controlled by phosphorylation of eIF2α (eukaryotic translation initiation factor-2α) have been described after energy deprivation. PKR (double-stranded RNA dependant protein kinase) is a pro-apoptotic kinase that phosphorylates eIF2α and modulates JNK activation in various cellular stresses. We investigated the relations between PKR, eIF2α and BACE1 in AD brains in APP/PS1 knock-in mice and in hydrogen peroxide-induced OS in human neuroblastoma (SH-SY5Y) cell cultures. Immunoblotting results showed that activated PKR (pPKR) and activated eIF2α (peIF2α) and BACE1 levels are increased in AD cortices and BACE1 correlate with phosphorylated eIF2α levels. BACE1 protein levels are increased in response to OS in SH-SY5Y cells and specific inhibitions of PKR-eIF2α attenuate BACE1 protein levels in this model. Our findings provide a new translational regulation of BACE1, under the control of PKR in OS, where eIF2α phosphorylation regulates BACE1 protein expression.
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Affiliation(s)
- François Mouton-Liger
- Service d'Histologie et de Biologie du Vieillissement, APHP, Groupe Hospitalier Lariboisière Fernand-Widal Saint-Louis, Université Paris VII, Paris, France.
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The mitochondria-targeted antioxidant MitoQ prevents loss of spatial memory retention and early neuropathology in a transgenic mouse model of Alzheimer's disease. J Neurosci 2011; 31:15703-15. [PMID: 22049413 DOI: 10.1523/jneurosci.0552-11.2011] [Citation(s) in RCA: 306] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Considerable evidence suggests that mitochondrial dysfunction and oxidative stress contribute to the progression of Alzheimer's disease (AD). We examined the ability of the novel mitochondria-targeted antioxidant MitoQ (mitoquinone mesylate: [10-(4,5-dimethoxy-2-methyl-3,6-dioxo-1,4-cycloheexadienl-yl) decyl triphenylphosphonium methanesulfonate]) to prevent AD-like pathology in mouse cortical neurons in cell culture and in a triple transgenic mouse model of AD (3xTg-AD). MitoQ attenuated β-amyloid (Aβ)-induced neurotoxicity in cortical neurons and also prevented increased production of reactive species and loss of mitochondrial membrane potential (Δψ(m)) in them. To determine whether the mitochondrial protection conferred by MitoQ was sufficient to prevent the emergence of AD-like neuropathology in vivo, we treated young female 3xTg-AD mice with MitoQ for 5 months and analyzed the effect on the progression of AD-like pathologies. Our results show that MitoQ prevented cognitive decline in these mice as well as oxidative stress, Aβ accumulation, astrogliosis, synaptic loss, and caspase activation in their brains. The work presented herein suggests a central role for mitochondria in neurodegeneration and provides evidence supporting the use of mitochondria-targeted therapeutics in diseases involving oxidative stress and metabolic failure, namely AD.
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Bang Y, Lim J, Kim SS, Jeong HM, Jung KK, Kang IH, Lee KY, Choi HJ. Aroclor1254 interferes with estrogen receptor-mediated neuroprotection against beta-amyloid toxicity in cholinergic SN56 cells. Neurochem Int 2011; 59:582-90. [DOI: 10.1016/j.neuint.2011.04.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 04/01/2011] [Accepted: 04/04/2011] [Indexed: 12/11/2022]
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59
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Juhász G, Földi I, Penke B. Systems biology of Alzheimer's disease: How diverse molecular changes result in memory impairment in AD. Neurochem Int 2011; 58:739-50. [DOI: 10.1016/j.neuint.2011.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 01/19/2011] [Accepted: 02/10/2011] [Indexed: 01/13/2023]
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Zhu D, Shi J, Zhang Y, Wang B, Liu W, Chen Z, Tong Q. Central angiotensin II stimulation promotes β amyloid production in Sprague Dawley rats. PLoS One 2011; 6:e16037. [PMID: 21297982 PMCID: PMC3030571 DOI: 10.1371/journal.pone.0016037] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 12/05/2010] [Indexed: 11/29/2022] Open
Abstract
Background Stress and various stress hormones, including catecholamines and glucocorticoids, have recently been implicated in the pathogenesis of Alzheimer's disease (AD), which represents the greatest unresolved medical challenge in neurology. Angiotensin receptor blockers have shown benefits in AD and prone-to-AD animals. However, the mechanisms responsible for their efficacy remain unknown, and no studies have directly addressed the role of central angiotensin II (Ang II), a fundamental stress hormone, in the pathogenesis of AD. The present study focused on the role of central Ang II in amyloidogenesis, the critical process in AD neuropathology, and aimed to provide direct evidence for the role of this stress hormone in the pathogenesis of AD. Methodology/Principal Findings Increased central Ang II levels during stress response were modeled by intracerebroventricular (ICV) administration of graded doses of Ang II (6 ng/hr low dose, 60 ng/hr medium dose, and 600 ng/hr high dose, all delivered at a rate of 0.25 µl/hr) to male Sprague Dawley rats (280–310 g) via osmotic pumps. After 1 week of continuous Ang II infusion, the stimulation of Ang II type 1 receptors was accompanied by the modulation of amyloid precursor protein, α-, β-and γ-secretase, and increased β amyloid production. These effects could be completely abolished by concomitant ICV infusion of losartan, indicating that central Ang II played a causative role in these alterations. Conclusions/Significance Central Ang II is essential to the stress response, and the results of this study suggest that increased central Ang II levels play an important role in amyloidogenesis during stress, and that central Ang II-directed stress prevention and treatment might represent a novel anti-AD strategy.
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Affiliation(s)
- Donglin Zhu
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jingping Shi
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
- * E-mail:
| | - Yingdong Zhang
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Bianrong Wang
- Department of Neurology, School of Medicine, Nanjing University, Nanjing, People's Republic of China
| | - Wei Liu
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Zhicong Chen
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qiang Tong
- Department of Neurology, Nanjing Brain Hospital, Nanjing Medical University, Nanjing, People's Republic of China
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Mohammadi M, Yazdanparast R. Modulation of H2O2-induced mitogen-activated protein kinases activation and cell death in SK-N-MC cells by EUK134, a salen derivative. Basic Clin Pharmacol Toxicol 2011; 108:378-84. [PMID: 21205220 DOI: 10.1111/j.1742-7843.2010.00664.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Alzheimer's disease is a neurodegenerative disorder that is characterized by the accumulation of senile plaques containing amyloid β (Aβ) and neurofibrillary tangles composed of hyperphosphorylated tau protein in the brain. Oxidative stress has been proposed to mediate Aβ-induced neurotoxicity. In that regard, we evaluated the ability of EUK134, a superoxide dismutase and catalase mimics, to protect human neuroblastoma cell line SK-N-MC against H(2)O(2) -induced oxidative stress. Our data clearly indicated that cell death induced by H(2)O(2) was reversed by EUK134. Likewise, lipid peroxidation, caspase-3 activation and intracellular reactive oxygen species formation all returned to control levels following pre-treatments with EUK134. Elevated phosphorylation of mitogen-activated protein kinases (MAPK) induced by H(2)O(2) in SK-N-MC cells was lowered by EUK134 in a dose-dependent manner. In addition, EUK134 decreased expression of pro-apoptotic genes p53 and Bax and enhanced expression of anti-apoptotic Bcl-2 gene. Taken together, these results suggest that EUK134 protects neuronal cells against H(2)O(2) toxicity by attenuating oxidative stress through inhibition of MAPK phosphorylation cascade.
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Affiliation(s)
- Mohsen Mohammadi
- Institute of Biochemistry and Biophysics, University of Tehran, Iran
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62
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Saxena U. Alzheimer's disease amyloid hypothesis at crossroads: where do we go from here? Expert Opin Ther Targets 2010; 14:1273-7. [DOI: 10.1517/14728222.2010.528285] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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63
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Insulin deficiency exacerbates cerebral amyloidosis and behavioral deficits in an Alzheimer transgenic mouse model. Mol Neurodegener 2010; 5:46. [PMID: 21044348 PMCID: PMC2987993 DOI: 10.1186/1750-1326-5-46] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 11/02/2010] [Indexed: 12/16/2022] Open
Abstract
Background Although increasing evidence has indicated that brain insulin dysfunction is a risk factor for Alzheimer disease (AD), the underlying mechanisms by which insulin deficiency may impact the development of AD are still obscure. Using a streptozotocin (STZ)-induced insulin deficient diabetic AD transgenic mouse model, we evaluated the effect of insulin deficiency on AD-like behavior and neuropathology. Results Our data showed that administration of STZ increased the level of blood glucose and reduced the level of serum insulin, and further decreased the phosphorylation levels of insulin receptors, and increased the activities of glycogen synthase kinase-3α/β and c-Jun N-terminal kinase in the APP/PS1 mouse brain. We further showed that STZ treatment promoted the processing of amyloid-β (Aβ) precursor protein resulting in increased Aβ generation, neuritic plaque formation, and spatial memory deficits in transgenic mice. Conclusions Our present data indicate that there is a close link between insulin deficient diabetes and cerebral amyloidosis in the pathogenesis of AD.
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Reddy PH, Manczak M, Mao P, Calkins MJ, Reddy AP, Shirendeb U. Amyloid-beta and mitochondria in aging and Alzheimer's disease: implications for synaptic damage and cognitive decline. J Alzheimers Dis 2010. [PMID: 20413847 DOI: 10.3233/jad-2010-100504.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This article reviews the role of amyloid-beta (Abeta) and mitochondria in synaptic damage and cognitive decline found in patients with Alzheimer's disease (AD). Recent molecular, cellular, animal model, and postmortem brain studies have revealed that Abeta and mitochondrial abnormalities are key factors that cause synaptic damage and cognitive decline in AD. Abeta is reported to accumulate in subcellular compartments and to impair the normal function of neurons in AD patients. Further, recent studies using biochemical methods and electron microscopy have revealed that the accumulation of Abeta at nerve terminals affect synaptic activities, including the release of neurotransmitters and synaptic vesicles. Recent studies of the relationship between mitochondria and Abeta in AD patients suggest that in mitochondria, structural changes caused by Abeta result in increased mitochondrial fragmentation, decreased mitochondrial fusion, mitochondrial dysfunction, and synaptic damage. This paper discusses the latest research on Abeta, mitochondria, age-dependent factors of AD in the brain, and synaptic damage in AD. This paper also briefly discusses potential mitochondrial therapeutics in the treatment of patients with AD.
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Affiliation(s)
- P Hemachandra Reddy
- Neurogenetics Laboratory, Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA.
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65
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Reddy PH, Manczak M, Mao P, Calkins MJ, Reddy AP, Shirendeb U. Amyloid-beta and mitochondria in aging and Alzheimer's disease: implications for synaptic damage and cognitive decline. J Alzheimers Dis 2010; 20 Suppl 2:S499-512. [PMID: 20413847 DOI: 10.3233/jad-2010-100504] [Citation(s) in RCA: 184] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This article reviews the role of amyloid-beta (Abeta) and mitochondria in synaptic damage and cognitive decline found in patients with Alzheimer's disease (AD). Recent molecular, cellular, animal model, and postmortem brain studies have revealed that Abeta and mitochondrial abnormalities are key factors that cause synaptic damage and cognitive decline in AD. Abeta is reported to accumulate in subcellular compartments and to impair the normal function of neurons in AD patients. Further, recent studies using biochemical methods and electron microscopy have revealed that the accumulation of Abeta at nerve terminals affect synaptic activities, including the release of neurotransmitters and synaptic vesicles. Recent studies of the relationship between mitochondria and Abeta in AD patients suggest that in mitochondria, structural changes caused by Abeta result in increased mitochondrial fragmentation, decreased mitochondrial fusion, mitochondrial dysfunction, and synaptic damage. This paper discusses the latest research on Abeta, mitochondria, age-dependent factors of AD in the brain, and synaptic damage in AD. This paper also briefly discusses potential mitochondrial therapeutics in the treatment of patients with AD.
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Affiliation(s)
- P Hemachandra Reddy
- Neurogenetics Laboratory, Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA.
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Dumont M, Lin MT, Beal MF. Mitochondria and antioxidant targeted therapeutic strategies for Alzheimer's disease. J Alzheimers Dis 2010; 20 Suppl 2:S633-43. [PMID: 20421689 DOI: 10.3233/jad-2010-100507] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Oxidative stress and mitochondrial dysfunction are important features present in Alzheimer's disease (AD). They appear early and contribute to disease progression, both in human postmortem AD brains as well as in transgenic AD mouse brains. For this reason, targeting oxidative stress and mitochondria in AD may lead to the development of promising therapeutic strategies. Several exogenous antioxidant compounds have been tested and found beneficial in transgenic AD mice, such as vitamins and spices. However, their efficacy was much more modest in human trials. More recently, new strategies have been elaborated to promote endogenous antioxidant systems. Different pathways involved in oxidative stress response have been identified. Compounds able to upregulate these pathways are being generated and tested in animal models of AD and in human patients. Upregulation of antioxidant gene expression was beneficial in mice, giving hope for future avenues in the treatment of AD and other neurodegenerative disorders.
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Affiliation(s)
- Magali Dumont
- Weill Cornell Medical College, Department of Neurology and Neuroscience, New York, NY, USA
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Jang SM, Kim JW, Kim CH, An JH, Kang EJ, Kim CG, Kim HJ, Choi KH. Control of transferrin expression by β-amyloid through the CP2 transcription factor. FEBS J 2010; 277:4054-65. [PMID: 20796026 DOI: 10.1111/j.1742-4658.2010.07801.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Accumulation of β-amyloid protein (Aβ) is one of the most important pathological features of Alzheimer's disease. Although Aβ induces neurodegeneration in the cortex and hippocampus through several molecular mechanisms, few studies have evaluated the modulation of transcription factors during Aβ-induced neurotoxicity. Therefore, in this study, we investigated the transcriptional activity of transcription factor CP2 in neuronal damage mediated by Aβ (Aβ(1-42) and Aβ(25-35) ). An unbiased motif search of the transferrin promoter region showed that CP2 binds to the transferrin promoter, an iron-regulating protein, and regulates transferrin transcription. Ectopic expression of CP2 led to increased transferrin expression at both the mRNA and protein levels, whereas knockdown of CP2 down-regulated transferrin mRNA and protein expression. Moreover, CP2 trans-activated transcription of a transferrin reporter gene. An electrophoretic mobility shift assay and a chromatin immunoprecipitation assay showed that CP2 binds to the transferrin promoter region. Furthermore, the binding affinity of CP2 to the transferrin promoter was regulated by Aβ, as Aβ (Aβ(1-42) and Aβ(25-35) ) markedly increased the binding affinity of CP2 for the transferrin promoter. Taken together, these results suggest that CP2 contributes to the pathogenesis of Alzheimer's disease by inducing transferrin expression via up-regulating its transcription.
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Affiliation(s)
- Sang-Min Jang
- Department of Life Science (BK21 Program), College of Natural Sciences, Chung-Ang University, Seoul, Korea
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68
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Inhibition of c-Jun kinase provides neuroprotection in a model of Alzheimer's disease. Neurobiol Dis 2010; 39:311-7. [PMID: 20451607 DOI: 10.1016/j.nbd.2010.04.015] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/13/2010] [Accepted: 04/26/2010] [Indexed: 11/22/2022] Open
Abstract
The c-Jun N-terminal kinase (JNK) pathway potentially links together the three major pathological hallmarks of Alzheimer's disease (AD): development of amyloid plaques, neurofibrillary tangles, and brain atrophy. As activation of the JNK pathway has been observed in amyloid models of AD in association with peri-plaque regions and neuritic dystrophy, as we confirm here for Tg2576/PS(M146L) transgenic mice, we directly tested whether JNK inhibition could provide neuroprotection in a novel brain slice model for amyloid precursor protein (APP)-induced neurodegeneration. We found that APP/amyloid beta (Abeta)-induced neurodegeneration is blocked by both small molecule and peptide inhibitors of JNK, and provide evidence that this neuroprotection occurs downstream of APP/Abeta production and processing. Our findings demonstrate that Abeta can induce neurodegeneration, at least in part, through the JNK pathway and suggest that inhibition of JNK may be of therapeutic utility in the treatment of AD.
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