1
|
Duan L, Bhattacharyya BJ, Belmadani A, Pan L, Miller RJ, Kessler JA. Stem cell derived basal forebrain cholinergic neurons from Alzheimer's disease patients are more susceptible to cell death. Mol Neurodegener 2014; 9:3. [PMID: 24401693 PMCID: PMC3896712 DOI: 10.1186/1750-1326-9-3] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 01/03/2014] [Indexed: 12/20/2022] Open
Abstract
An early substantial loss of basal forebrain cholinergic neurons (BFCNs) is a constant feature of Alzheimer’s disease (AD) and is associated with deficits in spatial learning and memory. Induced pluripotent stem cells (iPSCs) derived from patients with AD as well as from normal controls could be efficiently differentiated into neurons with characteristics of BFCNs. We used BFCNs derived from iPSCs to model sporadic AD with a focus on patients with ApoE3/E4 genotypes (AD-E3/E4). BFCNs derived from AD-E3/E4 patients showed typical AD biochemical features evidenced by increased Aβ42/Aβ40 ratios. AD-E3/E4 neurons also exhibited altered responses to treatment with γ-secretase inhibitors compared to control BFCNs or neurons derived from patients with familial AD. BFCNs from patients with AD-E3/E4 also exhibited increased vulnerability to glutamate-mediated cell death which correlated with increased intracellular free calcium upon glutamate exposure. The ability to generate BFCNs with an AD phenotype is a significant step both for understanding disease mechanisms and for facilitating screening for agents that promote synaptic integrity and neuronal survival.
Collapse
Affiliation(s)
- Lishu Duan
- Departments of Neurology, Northwestern University's Feinberg School of Medicine, Feinberg School of Medicine, 303 East Chicago Avenue, Chicago, IL 60611-3008, USA.
| | | | | | | | | | | |
Collapse
|
2
|
Cryptotanshinione upregulates α-secretase by activation PI3K pathway in cortical neurons. Brain Res 2010; 1348:165-73. [DOI: 10.1016/j.brainres.2010.05.083] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Revised: 05/25/2010] [Accepted: 05/26/2010] [Indexed: 11/30/2022]
|
3
|
Mei Z, Zhang F, Tao L, Zheng W, Cao Y, Wang Z, Tang S, Le K, Chen S, Pi R, Liu P. Cryptotanshinone, a compound from Salvia miltiorrhiza modulates amyloid precursor protein metabolism and attenuates beta-amyloid deposition through upregulating alpha-secretase in vivo and in vitro. Neurosci Lett 2009; 452:90-5. [PMID: 19154776 DOI: 10.1016/j.neulet.2009.01.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 12/29/2008] [Accepted: 01/07/2009] [Indexed: 11/19/2022]
Abstract
The amyloid precursor protein (APP) is cleaved enzymatically by non-amyloidogenic and amyloidogenic pathways. alpha-Secretase cleaves APP within beta-amyloid protein (Abeta) sequence, resulting in the release of a secreted fragment of APP (sAPPalpha) and precluding Abeta generation. Cryptotanshinone (CTS), an active component of the medicinal herb Salvia miltiorrhiza, has been shown to improve learning and memory in several pharmacological models of Alzheimer's disease (AD). However, the effects of CTS on the Abeta plaque pathology and the APP processing in AD are unclear. Here we reported that CTS strongly attenuated amyloid plaque deposition in the brain of APP/PS1 transgenic mice. In addition, CTS significantly improved spatial learning and memory in APP/PS1 mice assessed by the Morris water maze testing. To define the exact molecular mechanisms involved in the beneficial effects of CTS, we investigated the effects of the CTS on APP processing in rat cortical neuronal cells overexpressing Swedish mutant human APP695. CTS was found to decrease Abeta generation in concentration-dependent (0-10muM) manner. Interestingly, the N-terminal APP cleavage product, sAPPalpha was markedly increased by CTS. Further study showed that alpha-secretase activity was increased by CTS. Taken together, our results suggested CTS improved the cognitive ability in AD transgenic mice and promoted APP metabolism toward the non-amyloidogenic products pathway in rat cortical neuronal cells. CTS shows a promising novel way for the therapy of AD.
Collapse
Affiliation(s)
- Zhengrong Mei
- Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, PR China
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
4
|
Burton CR, Meredith JE, Barten DM, Goldstein ME, Krause CM, Kieras CJ, Sisk L, Iben LG, Polson C, Thompson MW, Lin XA, Corsa J, Fiedler T, Pierdomenico M, Cao Y, Roach AH, Cantone JL, Ford MJ, Drexler DM, Olson RE, Yang MG, Bergstrom CP, McElhone KE, Bronson JJ, Macor JE, Blat Y, Grafstrom RH, Stern AM, Seiffert DA, Zaczek R, Albright CF, Toyn JH. The amyloid-beta rise and gamma-secretase inhibitor potency depend on the level of substrate expression. J Biol Chem 2008; 283:22992-3003. [PMID: 18574238 DOI: 10.1074/jbc.m804175200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The amyloid-beta (Abeta) peptide, which likely plays a key role in Alzheimer disease, is derived from the amyloid-beta precursor protein (APP) through consecutive proteolytic cleavages by beta-site APP-cleaving enzyme and gamma-secretase. Unexpectedly gamma-secretase inhibitors can increase the secretion of Abeta peptides under some circumstances. This "Abeta rise" phenomenon, the same inhibitor causing an increase in Abeta at low concentrations but inhibition at higher concentrations, has been widely observed. Here we show that the Abeta rise depends on the beta-secretase-derived C-terminal fragment of APP (betaCTF) or C99 levels with low levels causing rises. In contrast, the N-terminally truncated form of Abeta, known as "p3," formed by alpha-secretase cleavage, did not exhibit a rise. In addition to the Abeta rise, low betaCTF or C99 expression decreased gamma-secretase inhibitor potency. This "potency shift" may be explained by the relatively high enzyme to substrate ratio under conditions of low substrate because increased concentrations of inhibitor would be necessary to affect substrate turnover. Consistent with this hypothesis, gamma-secretase inhibitor radioligand occupancy studies showed that a high level of occupancy was correlated with inhibition of Abeta under conditions of low substrate expression. The Abeta rise was also observed in rat brain after dosing with the gamma-secretase inhibitor BMS-299897. The Abeta rise and potency shift are therefore relevant factors in the development of gamma-secretase inhibitors and can be evaluated using appropriate choices of animal and cell culture models. Hypothetical mechanisms for the Abeta rise, including the "incomplete processing" and endocytic models, are discussed.
Collapse
Affiliation(s)
- Catherine R Burton
- Bristol-Myers Squibb Research and Development, Wallingford, Connecticut 06492, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Zhao G, Tan J, Mao G, Cui MZ, Xu X. The same gamma-secretase accounts for the multiple intramembrane cleavages of APP. J Neurochem 2007; 100:1234-46. [PMID: 17241131 DOI: 10.1111/j.1471-4159.2006.04302.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It has been hypothesized that different C-terminus of beta-amyloid peptide (Abeta) may be generated by different gamma-secretase activities. Recently, we have identified a new zeta-cleavage site at Abeta46, leading to an important finding that the C-terminus of Abeta is produced by a series of sequential cleavages. This finding prompted us to examine the effects of the known gamma-secretase inhibitors on different steps of the gamma-secretase-mediated sequential cleavages and specifically their effects on the formation and turnover of the intermediate Abeta(46). Our results demonstrate that some of the known inhibitors, such as L-685,458 and III-31C as well as inhibitors IV and V, inhibit the formation of secreted Abeta(40/42) by inhibiting the formation of the intermediate Abeta(46). However, most of the other inhibitors show no inhibitory effect on the formation of the intermediate Abeta(46), but rather inhibit the turnover of Abeta(46), resulting in its accumulation. In addition, the non-steroidal anti-inflammatory drugs (NSAIDs) ibuprofen and sulindac sulfide have no effect on the formation and turnover of Abeta(46), but rather modulate the ratio of secreted Abeta at a step after the formation of Abeta(40) and Abeta(42). Thus, our data strongly suggest that the multi-sequential intramembrane cleavages of amyloid precursor protein C (APP) are likely catalyzed by the same gamma-secretase.
Collapse
Affiliation(s)
- Guojun Zhao
- Department of Pathobiology, College of Veterinary Medicine, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | | | | | | | | |
Collapse
|
6
|
Shen J, Kelleher RJ. The presenilin hypothesis of Alzheimer's disease: evidence for a loss-of-function pathogenic mechanism. Proc Natl Acad Sci U S A 2007; 104:403-9. [PMID: 17197420 PMCID: PMC1766397 DOI: 10.1073/pnas.0608332104] [Citation(s) in RCA: 339] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dominantly inherited mutations in the genes encoding presenilins (PS) and the amyloid precursor protein (APP) are the major causes of familial Alzheimer's disease (AD). The prevailing view of AD pathogenesis posits that accumulation of beta-amyloid (Abeta) peptides, particularly Abeta42, is the central event triggering neurodegeneration. Emerging evidence, however, suggests that loss of essential functions of PS could better explain dementia and neurodegeneration in AD. First, conditional inactivation of PS in the adult mouse brain causes progressive memory loss and neurodegeneration resembling AD, whereas mouse models based on overproduction of Abeta have failed to produce neurodegeneration. Second, whereas pathogenic PS mutations enhance Abeta42 production, they typically reduce Abeta40 generation and impair other PS-dependent activities. Third, gamma-secretase inhibitors can enhance the production of Abeta42 while blocking other gamma-secretase activities, thus mimicking the effects of PS mutations. Finally, PS mutations have been identified in frontotemporal dementia, which lacks amyloid pathology. Based on these and other observations, we propose that partial loss of PS function may underlie memory impairment and neurodegeneration in the pathogenesis of AD. We also speculate that Abeta42 may act primarily to antagonize PS-dependent functions, possibly by operating as an active site-directed inhibitor of gamma-secretase.
Collapse
Affiliation(s)
- Jie Shen
- *Center for Neurologic Diseases, Brigham and Women's Hospital
- Program in Neuroscience and Department of Neurology, Harvard Medical School, Boston, MA 02115
- To whom correspondence may be addressed. E-mail:
or
| | - Raymond J. Kelleher
- Center for Human Genetic Research and Harvard-Partners Center for Genetics and Genomics, Massachusetts General Hospital, and
- Program in Neuroscience and Department of Neurology, Harvard Medical School, Boston, MA 02115
- To whom correspondence may be addressed. E-mail:
or
| |
Collapse
|
7
|
Rockenstein E, Torrance M, Mante M, Adame A, Paulino A, Rose JB, Crews L, Moessler H, Masliah E. Cerebrolysin decreases amyloid-beta production by regulating amyloid protein precursor maturation in a transgenic model of Alzheimer's disease. J Neurosci Res 2006; 83:1252-61. [PMID: 16511867 DOI: 10.1002/jnr.20818] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cerebrolysin is a peptide mixture with neurotrophic effects that might reduce the neurodegenerative pathology in Alzheimer's disease (AD). We have previously shown in an amyloid protein precursor (APP) transgenic (tg) mouse model of AD-like neuropathology that Cerebrolysin ameliorates behavioral deficits, is neuroprotective, and decreases amyloid burden; however, the mechanisms involved are not completely clear. Cerebrolysin might reduce amyloid deposition by regulating amyloid-beta (Abeta) degradation or by modulating APP expression, maturation, or processing. To investigate these possibilities, APP tg mice were treated for 6 months with Cerebrolysin and analyzed in the water maze, followed by RNA, immunoblot, and confocal microscopy analysis of full-length (FL) APP and its fragments, beta-secretase (BACE1), and Abeta-degrading enzymes [neprilysin (Nep) and insulin-degrading enzyme (IDE)]. Consistent with previous studies, Cerebrolysin ameliorated the performance deficits in the spatial learning portion of the water maze and reduced the synaptic pathology and amyloid burden in the brains of APP tg mice. These effects were associated with reduced levels of FL APP and APP C-terminal fragments, but levels of BACE1, Notch1, Nep, and IDE were unchanged. In contrast, levels of active cyclin-dependent kinase-5 (CDK5) and glycogen synthase kinase-3beta [GSK-3beta; but not stress-activated protein kinase-1 (SAPK1)], kinases that phosphorylate APP, were reduced. Furthermore, Cerebrolysin reduced the levels of phosphorylated APP and the accumulation of APP in the neuritic processes. Taken together, these results suggest that Cerebrolysin might reduce AD-like pathology in the APP tg mice by regulating APP maturation and transport to sites where Abeta protein is generated. This study clarifies the mechanisms through which Cerebrolysin might reduce Abeta production and deposition in AD and further supports the importance of this compound in the potential treatment of early AD.
Collapse
Affiliation(s)
- Edward Rockenstein
- Department of Neurosciences, University of California San Diego, School of Medicine, La Jolla, California 92093-0624, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Meyer EL, Strutz N, Gahring LC, Rogers SW. Glutamate receptor subunit 3 is modified by site-specific limited proteolysis including cleavage by gamma-secretase. J Biol Chem 2003; 278:23786-96. [PMID: 12700243 DOI: 10.1074/jbc.m301360200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ionotropic glutamate receptor (GluR) expression and function is regulated through multiple pre- and post-translational mechanisms. We find that limited proteolytic cleavage of GluR3 at two distinct sites generates stable GluR3 short forms that are glycosylated and found in association with other full-length GluRs in the mouse brain and cultured primary neurons. A combination of mutagenesis and transfection into HEK293 cells revealed cleavage by a gamma-secretase-like activity within the membrane-localized re-entry loop at or near the leucine-glycine pair (amino acids 585-586, GluR3sbeta) and a second site within a proline-rich PEST-like sequence in the first cytoplasmic loop (Asp570-Pro571, GluR3salpha). Generation of the prominent GluR3salpha form was effectively abolished in the mutant, GluR3D570A, but inhibitors of lysosomes, the proteasome, caspases, or calpains had no effect. The possible impact of cleavage on receptor function was suggested when the co-expression of the GluR3P571Stop mutant (creating GluR3salpha) co-assembled with other GluR subunits and decreased receptor function in Xenopus oocytes. In transiently transfected HEK293 cells, co-expression of GluR3salpha alters the relative association between GluR1 and GluR3 during assembly, and the presence of the novel C-terminal proline-rich domain of GluR3salpha imparts lateral membrane mobility to GluR complexes. These results suggest that limited proteolysis is another post-translational mechanism through which functional diversity and specialization between closely related GluR subunits is accomplished.
Collapse
Affiliation(s)
- Erin L Meyer
- Salt Lake City Veteran's Affairs Geriatrics Research, Education and Clinical Center, University of Utah, Salt Lake City, Utah 84132, USA
| | | | | | | |
Collapse
|
9
|
Campbell WA, Reed MLO, Strahle J, Wolfe MS, Xia W. Presenilin endoproteolysis mediated by an aspartyl protease activity pharmacologically distinct from gamma-secretase. J Neurochem 2003; 85:1563-74. [PMID: 12787075 DOI: 10.1046/j.1471-4159.2003.01799.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Presenilin (PS)-dependent gamma-secretase cleavage is the final proteolytic step in generating amyloid beta protein (A beta), a key peptide involved in the pathogenesis of Alzheimer's disease. PS undergoes endoproteolysis by an unidentified 'presenilinase' to generate the functional N-terminal and C-terminal fragment heterodimers (NTF/CTF) that may harbor the gamma-secretase active site. To better understand the relationship between presenilinase and gamma-secretase, we characterized the biochemical properties of presenilinase and compared them with those of gamma-secretase. Similar to gamma-secretase, presenilinase was most active at acidic pH 6.3. Aspartyl protease inhibitor pepstatin A blocked presenilinase activity with an IC50 of approximately 1 microM. Difluoroketone aspartyl protease transition state analogue MW167 was relatively selective for presenilinase (IC50 < 1 microM) over gamma-secretase (IC50-16 microM). Importantly, removing the transition state mimicking moiety simultaneously abolished both presenilinase and gamma-secretase inhibition, suggesting that presenilinase, like gamma-secretase, is an aspartyl protease. Interestingly, several of the most potent gamma-secretase inhibitors (IC50 = 0.3 or 20 nM) failed to block presenilinase activity. Although de novo generation of PS1 fragments coincided with production of A beta in vitro, blocking presenilinase activity without reducing pre-existing fragment levels permitted normal de novo generation of A beta and amyloid intracellular domain. Therefore, presenilinase has characteristics of an aspartyl protease, but this activity is distinct from gamma-secretase.
Collapse
Affiliation(s)
- William A Campbell
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | | | | | | |
Collapse
|
10
|
Gasic-Milenkovic J, Dukic-Stefanovic S, Deuther-Conrad W, Gärtner U, Münch G. Beta-amyloid peptide potentiates inflammatory responses induced by lipopolysaccharide, interferon -gamma and 'advanced glycation endproducts' in a murine microglia cell line. Eur J Neurosci 2003; 17:813-21. [PMID: 12603271 DOI: 10.1046/j.1460-9568.2003.02506.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
beta-Amyloid (Abeta) plaques are characteristic hallmarks of Alzheimer's disease (AD). In AD, it has been suggested that activation of microglial cells might be the link between Abeta deposition and neuronal degeneration. Activated microglia are associated with senile plaques and produce free radicals and inflammatory cytokines. However, it is still not clear whether Abeta needs a prestimulated environment to exert its proinflammatory potential. Advanced glycation endproducts (AGEs), protein-bound oxidation products of sugars, have been shown to accumulate in senile plaques and could induce a silent but chronic inflammation in the AD brain. We tested whether Abeta acts as an amplifier of a submaximal proinflammatory response initiated by exposure to chicken egg albumin-AGE, lipopolysaccharide or interferon-gamma. Synthetic Abeta was used to produce three different samples (Abeta-fibrilar; Abeta-aggregated; Abeta-AGE), which were characterized for beta-sheeted fibrils by the thioflavin-T test and electron microscopy. As markers of microglial activation, nitric oxide, interleukin-6, macrophage-colony stimulation factor and tumour necrosis factor-alpha production was measured. All three Abeta samples alone could not induce a detectable microglial response. The combination of Abeta preparations, however, with the coinducers provoked a strong microglial response, whereby Abeta-AGE and fibrilar Abeta were more potent inflammatory signals than aggregated Abeta. Thus, Abeta in senile plaques can amplify microglial activation by a coexisting submaximal inflammatory stimulus. Hence, anti-inflammatory therapeutics could either target the primary proinflammatory signal (e.g. by limiting AGE-formation by AGE inhibitors or cross-link breakers) or the amplifyer Abeta (e.g. by limiting Abeta production by beta- or gamma-secretase inhibitors).
Collapse
Affiliation(s)
- Jovana Gasic-Milenkovic
- Neuroimmunological Cell Biology Unit, Interdisciplinary Centre of Clinical Research (IZKF) Leipzig, Johannisallee 30a, 04103 Leipzig, Germany
| | | | | | | | | |
Collapse
|
11
|
De Felice FG, Ferreira ST. Beta-amyloid production, aggregation, and clearance as targets for therapy in Alzheimer's disease. Cell Mol Neurobiol 2002; 22:545-63. [PMID: 12585679 DOI: 10.1023/a:1021832302524] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
1. Despite major efforts aimed at elucidating the molecular basis and physiopathology of Alzheimer's disease (AD), there is still no effective treatment available for this devastating disorder. The biological mechanisms underlying the development of AD are complex, as multiple factors appear to modulate (either positively or negatively) the progression of neurodegeneration in the brains of AD patients. Not surprisingly, a number of different therapeutic approaches aimed at distinct aspects of the disease are currently being pursued. Given its central role in the neuropathology of AD, the beta-amyloid peptide (Abeta) is the focus of many such approaches. 2. In this review, we discuss recent developments along three major lines of investigation: (i) identification and characterization of inhibitors of the enzymes involved in proteolytic processing of the amyloid precursor protein and production of Abeta; (ii) identification of the pathways involved in cerebral degradation and clearance of Abeta; and (iii) characterization of small-molecule inhibitors of amyloid aggregation that prevent cerebral amyloid deposition and neurotoxicity. 3. Significant progress has been achieved in these directions, opening up new perspectives toward the development of effective approaches for the treatment or prevention of AD.
Collapse
Affiliation(s)
- Fernanda G De Felice
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
| | | |
Collapse
|
12
|
Maiorini AF, Gaunt MJ, Jacobsen TM, McKay AE, Waldman LD, Raffa RB. Potential novel targets for Alzheimer pharmacotherapy: I. Secretases. J Clin Pharm Ther 2002; 27:169-83. [PMID: 12081630 DOI: 10.1046/j.1365-2710.2002.00415.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The prevailing major theory of Alzheimer's disease (AD) is that insoluble amyloid beta-peptide (Abeta) found in the cerebral plaques characteristic of the disease is causative or is at least a contributing factor. According to this theory, inhibition of aberrant Abeta production should prevent or at least limit the extent of AD pathophysiology. As three 'secretase' enzymes (alpha, beta and gamma) catalyse the proteolytic cleavage of amyloid precursor protein (APP) (the precursor protein of Abeta), one or more secretases have become targets for potential novel AD pharmacotherapy. Secretase inhibitors have been designed and are in various stages of development. The clinical trials of these compounds will, if positive, result in drugs with dramatically better clinical efficacy or, if negative, will force a reassessment of the theory about the role of Abeta in AD.
Collapse
Affiliation(s)
- A F Maiorini
- Temple University School of Pharmacy, Philadelphia, PA 19140, USA
| | | | | | | | | | | |
Collapse
|
13
|
Defelice FG, Ferreira ST. Physiopathological modulators of amyloid aggregation and novel pharmacological approaches in Alzheimer's disease. AN ACAD BRAS CIENC 2002; 74:265-84. [PMID: 12098753 DOI: 10.1590/s0001-37652002000200006] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The biological mechanisms underlying the neuropathology of Alzheimer's disease (AD) are complex, as several factors likely contribute to the development of the disease. Therefore, it is not surprising that a number of different possible therapeutic approaches addressing distinct aspects of this disease are currently being investigated. Among these are ways to prevent amyloid aggregation and/or deposition, to prevent neuronal degeneration, and to increase brain neurotransmitter levels. Here, we discuss possible roles of endogenous modulators of Abeta aggregation in the physiopathology of AD and some of the strategies currently under consideration to interfere with brain levels of beta-amyloid, its aggregation and neurotoxicity.
Collapse
Affiliation(s)
- Fernanda G Defelice
- Department of Medical Biochemistry, Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Brazil
| | | |
Collapse
|
14
|
Berechid BE, Kitzmann M, Foltz DR, Roach AH, Seiffert D, Thompson LA, Olson RE, Bernstein A, Donoviel DB, Nye JS. Identification and characterization of presenilin-independent Notch signaling. J Biol Chem 2002; 277:8154-65. [PMID: 11756438 DOI: 10.1074/jbc.m108238200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Presenilin (PS) proteins control the proteolytic cleavage that precedes nuclear access of the Notch intracellular domain. Here we observe that a partial activation of the HES1 promoter can be detected in PS1/PS2 (PS1/2) double null cells using Notch1 Delta E constructs or following Delta 1 stimulation, despite an apparent abolition of the production and nuclear accumulation of the Notch intracellular domain. PS1/2-independent Notch activation is sensitive to Numblike, a physiological inhibitor of Notch. PS1/2-independent Notch signaling is also inhibited by an active gamma-secretase inhibitor in the low micromolar range and is not inhibited by an inactive analogue, similar to PS-dependent Notch signaling. However, experiments using a Notch1-Gal4-VP16 fusion protein indicate that the PS1/2-independent activity does not release Gal4-VP16 and is therefore unlikely to proceed via an intramembranous cleavage. These data reveal that a novel PS1/2-independent mechanism plays a partial role in Notch signal transduction.
Collapse
MESH Headings
- Amyloid Precursor Protein Secretases
- Animals
- Aspartic Acid Endopeptidases
- Blotting, Northern
- Blotting, Western
- Cell Line
- Cell Membrane/metabolism
- Cell Nucleus/metabolism
- DNA/metabolism
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Electrophoresis, Polyacrylamide Gel
- Endopeptidases/metabolism
- Etoposide/pharmacology
- Intracellular Signaling Peptides and Proteins
- Ligands
- Luciferases/metabolism
- Membrane Proteins/genetics
- Membrane Proteins/physiology
- Mice
- Microscopy, Fluorescence
- Mutation
- Nerve Tissue Proteins/metabolism
- Nucleic Acid Synthesis Inhibitors/pharmacology
- Precipitin Tests
- Presenilin-1
- Presenilin-2
- Promoter Regions, Genetic
- Protein Binding
- Protein Structure, Tertiary
- Receptors, Notch
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- Time Factors
- Transcription, Genetic
- Transfection
Collapse
Affiliation(s)
- Bridget E Berechid
- Department of Molecular Pharmacology/Biological Chemistry, Northwestern University, Chicago, Illinois 60611, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Effects of Cerebrolysin™ on amyloid-β deposition in a transgenic model of Alzheimer’s disease. AGEING AND DEMENTIA CURRENT AND FUTURE CONCEPTS 2002. [DOI: 10.1007/978-3-7091-6139-5_31] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|