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Type 2 Diabetes, Obesity, and Risk for Dementia: Recent Insights into Brain Insulin Resistance and Hypometabolism. Curr Behav Neurosci Rep 2016. [DOI: 10.1007/s40473-016-0093-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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de la Monte SM, Re E, Longato L, Tong M. Dysfunctional pro-ceramide, ER stress, and insulin/IGF signaling networks with progression of Alzheimer's disease. J Alzheimers Dis 2012; 30 Suppl 2:S217-29. [PMID: 22297646 DOI: 10.3233/jad-2012-111728] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In Alzheimer's disease (AD), brain insulin and insulin-like growth factor (IGF) resistance and deficiency begin early, and worsen with severity of disease. The factors mediating progression of brain insulin/IGF resistance in AD are not well understood. We hypothesize that AD progression is mediated via negative cross-talk that promotes toxic ceramide generation and endoplasmic reticulum (ER) stress. The rationale is that insulin resistance dysregulates lipid metabolism and promotes ceramide accumulation, and thereby increases inflammation and stress. Consequences include disruption of cytoskeletal function and AβPP-Aβ secretion. The present study correlates AD stage with activation of pro-ceramide genes, ceramide levels, and molecular indices of ER stress in postmortem human brain tissue. The results demonstrated that in AD, brain insulin/IGF resistance was associated with constitutive activation of multiple pro-ceramide genes, increased ceramide levels, and increased expression of pro-ER stress pathway genes and proteins. Expression of several pro-ceramide and pro-apoptotic ER stress pathway molecules increased with AD severity and brain insulin/IGF resistance. In contrast, ER stress molecules that help maintain homeostasis with respect to unfolded protein responses were mainly upregulated in the intermediate rather than late stage of AD. These findings support our hypothesis that in AD, a triangulated mal-signaling network initiated by brain insulin/IGF resistance is propagated by the dysregulation of ceramide and ER stress homeostasis, which themselves promote insulin resistance. Therefore, once established, this reverberating loop must be targeted using multi-pronged approaches to disrupt the AD neurodegeneration cascade.
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Affiliation(s)
- Suzanne M de la Monte
- Department of Pathology (Neuropathology), Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA. Suzanne DeLaMonte
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Carrasquillo MM, Belbin O, Zou F, Allen M, Ertekin-Taner N, Ansari M, Wilcox SL, Kashino MR, Ma L, Younkin LH, Younkin SG, Younkin CS, Dincman TA, Howard ME, Howell CC, Stanton CM, Watson CM, Crump M, Vitart V, Hayward C, Hastie ND, Rudan I, Campbell H, Polasek O, Brown K, Passmore P, Craig D, McGuinness B, Todd S, Kehoe PG, Mann DM, Smith AD, Beaumont H, Warden D, Holmes C, Heun R, Kölsch H, Kalsheker N, Pankratz VS, Dickson DW, Graff-Radford NR, Petersen RC, Wright AF, Younkin SG, Morgan K. Concordant association of insulin degrading enzyme gene (IDE) variants with IDE mRNA, Abeta, and Alzheimer's disease. PLoS One 2010; 5:e8764. [PMID: 20098734 PMCID: PMC2808243 DOI: 10.1371/journal.pone.0008764] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 12/17/2009] [Indexed: 12/18/2022] Open
Abstract
Background The insulin-degrading enzyme gene (IDE) is a strong functional and positional candidate for late onset Alzheimer's disease (LOAD). Methodology/Principal Findings We examined conserved regions of IDE and its 10 kb flanks in 269 AD cases and 252 controls thereby identifying 17 putative functional polymorphisms. These variants formed eleven haplotypes that were tagged with ten variants. Four of these showed significant association with IDE transcript levels in samples from 194 LOAD cerebella. The strongest, rs6583817, which has not previously been reported, showed unequivocal association (p = 1.5×10−8, fold-increase = 2.12,); the eleven haplotypes were also significantly associated with transcript levels (global p = 0.003). Using an in vitro dual luciferase reporter assay, we found that rs6583817 increases reporter gene expression in Be(2)-C (p = 0.006) and HepG2 (p = 0.02) cell lines. Furthermore, using data from a recent genome-wide association study of two Croatian isolated populations (n = 1,879), we identified a proxy for rs6583817 that associated significantly with decreased plasma Aβ40 levels (ß = −0.124, p = 0.011) and total measured plasma Aβ levels (b = −0.130, p = 0.009). Finally, rs6583817 was associated with decreased risk of LOAD in 3,891 AD cases and 3,605 controls. (OR = 0.87, p = 0.03), and the eleven IDE haplotypes (global p = 0.02) also showed significant association. Conclusions Thus, a previously unreported variant unequivocally associated with increased IDE expression was also associated with reduced plasma Aß40 and decreased LOAD susceptibility. Genetic association between LOAD and IDE has been difficult to replicate. Our findings suggest that targeted testing of expression SNPs (eSNPs) strongly associated with altered transcript levels in autopsy brain samples may be a powerful way to identify genetic associations with LOAD that would otherwise be difficult to detect.
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Affiliation(s)
- Minerva M. Carrasquillo
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Olivia Belbin
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Fanggeng Zou
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Mariet Allen
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
- Medical Research Council (MRC) Human Genetics Unit, The Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Nilufer Ertekin-Taner
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
- Department of Neurology, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Morad Ansari
- Medical Research Council (MRC) Human Genetics Unit, The Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Samantha L. Wilcox
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Mariah R. Kashino
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Li Ma
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Linda H. Younkin
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Samuel G. Younkin
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Curtis S. Younkin
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Toros A. Dincman
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Melissa E. Howard
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Chanley C. Howell
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Chloe M. Stanton
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Christopher M. Watson
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Michael Crump
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Veronique Vitart
- Medical Research Council (MRC) Human Genetics Unit, The Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Caroline Hayward
- Medical Research Council (MRC) Human Genetics Unit, The Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Nicholas D. Hastie
- Medical Research Council (MRC) Human Genetics Unit, The Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Igor Rudan
- Department of Public Health Sciences, University of Edinburgh Medical School, Edinburgh, Scotland, United Kingdom
- Croatian Centre for Global Health, University of Split Medical School, Split, Croatia
- Centre for Clinical Medical Research, University Hospital “Sestre Milosrdnice”, Zagreb, Croatia
| | - Harry Campbell
- Department of Public Health Sciences, University of Edinburgh Medical School, Edinburgh, Scotland, United Kingdom
| | - Ozren Polasek
- Department of Public Health Sciences, University of Edinburgh Medical School, Edinburgh, Scotland, United Kingdom
- Centre for Clinical Medical Research, University Hospital “Sestre Milosrdnice”, Zagreb, Croatia
| | - Kristelle Brown
- School of Molecular Medical Sciences, Institute of Genetics, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - Peter Passmore
- Division of Psychiatry and Neuroscience, School of Medicine and Dentistry, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
| | - David Craig
- Division of Psychiatry and Neuroscience, School of Medicine and Dentistry, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
| | - Bernadette McGuinness
- Division of Psychiatry and Neuroscience, School of Medicine and Dentistry, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
| | - Stephen Todd
- Division of Psychiatry and Neuroscience, School of Medicine and Dentistry, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom
| | - Patrick G. Kehoe
- Department of Clinical Science at North Bristol, University of Bristol, Frenchay Hospital, Bristol, United Kingdom
| | - David M. Mann
- Greater Manchester Neurosciences Centre, University of Manchester, Manchester, United Kingdom
| | - A. David Smith
- Oxford Project to Investigate Memory and Ageing (OPTIMA), University Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Helen Beaumont
- Oxford Project to Investigate Memory and Ageing (OPTIMA), University Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Donald Warden
- Oxford Project to Investigate Memory and Ageing (OPTIMA), University Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Clive Holmes
- Memory Assessment and Research Centre, University of Southampton, Southampton, United Kingdom
| | - Reinhard Heun
- Division of Neuroscience, University of Birmingham, Birmingham, United Kingdom
| | - Heike Kölsch
- Department of Psychiatry, University of Bonn, Bonn, Germany
| | - Noor Kalsheker
- School of Molecular Medical Sciences, Institute of Genetics, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
| | - V. Shane Pankratz
- Department of Biostatistics, Mayo Clinic and Mayo Foundation, Rochester, Minnesota, United States of America
| | - Dennis W. Dickson
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Neill R. Graff-Radford
- Department of Neurology, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
| | - Ronald C. Petersen
- Department of Neurology and the Mayo Alzheimer Disease Research Center, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Alan F. Wright
- Medical Research Council (MRC) Human Genetics Unit, The Institute of Genetics and Molecular Medicine, Western General Hospital, Edinburgh, United Kingdom
| | - Steven G. Younkin
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, Florida, United States of America
- * E-mail:
| | - Kevin Morgan
- School of Molecular Medical Sciences, Institute of Genetics, Queen's Medical Centre, University of Nottingham, Nottingham, United Kingdom
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Lloyd SE, Rossor M, Fox N, Mead S, Collinge J. HECTD2, a candidate susceptibility gene for Alzheimer's disease on 10q. BMC MEDICAL GENETICS 2009; 10:90. [PMID: 19754925 PMCID: PMC2753310 DOI: 10.1186/1471-2350-10-90] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 09/15/2009] [Indexed: 12/31/2022]
Abstract
Background Late onset Alzheimer's disease (LOAD) is a neurodegenerative disorder characterised by the deposition of amyloid plaques and neurofibrillary tangles in the brain and is the major cause of dementia. Multiple genetic loci, including 10q, have been implicated in LOAD but to date, with the exception of APOE, the underlying genes have not been identified. HECTD2 maps to 10q and has been implicated in susceptibility to human prion diseases which are also neurodegenerative conditions associated with accumulation of misfolded host proteins. In this study we test whether the HECTD2 susceptibility allele seen in prion disease is also implicated in LOAD. Methods DNA from 320 individuals with Alzheimer's disease and 601 controls were genotyped for a HECTD2 intronic tagging SNP, rs12249854 (A/T). Groups were further analysed following stratification by APOE genotype. Results The rs12249854 minor allele (A) frequency was higher (5.8%) in the Alzheimer's disease group as compared to the controls (3.9%), however, this was not statistically significant (P = 0.0668). No significant difference was seen in minor allele frequency in the presence or absence of the APOE ε4 allele. Conclusion The common haplotypes of HECTD2, tagged by rs12249854, are not associated with susceptibility to LOAD.
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Affiliation(s)
- Sarah E Lloyd
- MRC Prion Unit, Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK.
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Abstract
Emerging data demonstrate pivotal roles for brain insulin resistance and insulin deficiency as mediators of cognitive impairment and neurodegeneration, particularly Alzheimer's disease (AD). Insulin and insulin-like growth factors (IGFs) regulate neuronal survival, energy metabolism, and plasticity, which are required for learning and memory. Hence, endogenous brain-specific impairments in insulin and IGF signaling account for the majority of AD-associated abnormalities. However, a second major mechanism of cognitive impairment has been linked to obesity and Type 2 diabetes (T2DM). Human and experimental animal studies revealed that neurodegeneration associated with peripheral insulin resistance is likely effectuated via a liver-brain axis whereby toxic lipids, including ceramides, cross the blood brain barrier and cause brain insulin resistance, oxidative stress, neuro-inflammation, and cell death. In essence, there are dual mechanisms of brain insulin resistance leading to AD-type neurodegeneration: one mediated by endogenous, CNS factors; and the other, peripheral insulin resistance with excess cytotoxic ceramide production.
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Affiliation(s)
- Suzanne M de la Monte
- Department of Neurology, Rhode Island Hospital and the Warren Alpert Medical School of Brown University, Providence, RI, USA.
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Song ES, Cady C, Fried MG, Hersh LB. Proteolytic fragments of insulysin (IDE) retain substrate binding but lose allosteric regulation. Biochemistry 2006; 45:15085-91. [PMID: 17154546 PMCID: PMC2519894 DOI: 10.1021/bi061298u] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Treatment of an N-terminal-containing His6-tagged insulysin (His6-IDE) with proteinase K led to the initial cleavage of the His tag and linker region. This was followed by C-terminal cleavages resulting in intermediate fragments of approximately 95 and approximately 76 kDa and finally a relatively stable approximately 56 kDa fragment. The approximately 76 and approximately 56 kDa fragments exhibited a low level of catalytic activity but retained the ability to bind the substrate with a similar affinity as the native enzyme. The kinetics of the reaction of the IDE approximately 76 and approximately 56 kDa proteolytic fragments with a synthetic fluorogenic substrate produced hyperbolic substrate versus velocity curves, rather than the sigmoidal curve obtained with His6-IDE. The approximately 76 and approximately 56 kDa IDE proteolytic fragments were active toward the physiological peptides beta-endorphin, insulin, and amyloid beta peptide 1-40. Although activity was reduced by a factor of approximately 103-104 with these substrates, the relative activity and the cleavage sites were unchanged. Both the approximately 76 and approximately 56 kDa fragments retained the regulatory cationic binding site that binds ATP. Thus, the two proteinase K cleavage fragments of IDE retain the substrate- and ATP-binding sites but have low catalytic activity and lose the allosteric kinetic behavior of IDE. These data suggest a role of the C-terminal region of IDE in allosteric regulation.
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Affiliation(s)
- Eun Suk Song
- Department of Molecular and Cellular Biochemistry and the Center for Structural Biology, University of Kentucky
| | - Clint Cady
- Department of Molecular and Cellular Biochemistry and the Center for Structural Biology, University of Kentucky
| | - Michael G. Fried
- Department of Molecular and Cellular Biochemistry and the Center for Structural Biology, University of Kentucky
| | - Louis B. Hersh
- Department of Molecular and Cellular Biochemistry and the Center for Structural Biology, University of Kentucky
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Wang YJ, Zhou HD, Zhou XF. Clearance of amyloid-beta in Alzheimer's disease: progress, problems and perspectives. Drug Discov Today 2006; 11:931-8. [PMID: 16997144 DOI: 10.1016/j.drudis.2006.08.004] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 07/14/2006] [Accepted: 08/11/2006] [Indexed: 11/25/2022]
Abstract
Alzheimer's disease (AD) is the most common form of senile dementia and the fourth highest cause of disability and death in the elderly. Amyloid-beta (Abeta) has been widely implicated in the etiology of AD. Several mechanisms have been proposed for Abeta clearance, including receptor-mediated Abeta transport across the blood-brain barrier and enzyme-mediated Abeta degradation. Moreover, pre-existing immune responses to Abeta might also be involved in Abeta clearance. In AD, such mechanisms appear to have become impaired. Recently, therapeutic approaches for Abeta clearance, targeting immunotherapy and molecules binding Abeta, have been developed. In this review, we discuss recent progress and problems with respect to Abeta clearance mechanisms and propose strategies for the development of therapeutics targeting Abeta clearance.
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Affiliation(s)
- Yan-Jiang Wang
- Department of Human Physiology and Centre for Neuroscience, Flinders University, Adelaide 5042, Australia
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Lynch JA, George AM, Eisenhauer PB, Conn K, Gao W, Carreras I, Wells JM, McKee A, Ullman MD, Fine RE. Insulin degrading enzyme is localized predominantly at the cell surface of polarized and unpolarized human cerebrovascular endothelial cell cultures. J Neurosci Res 2006; 83:1262-70. [PMID: 16511862 DOI: 10.1002/jnr.20809] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Insulin degrading enzyme (IDE) is expressed in the brain and may play an important role there in the degradation of the amyloid beta peptide (Abeta). Our results show that cultured human cerebrovascular endothelial cells (HCECs), a primary component of the blood-brain barrier, express IDE and may respond to exposure to low levels of Abeta by upregulating its expression. When radiolabeled Abeta is introduced to the medium of cultured HCECs, it is rapidly degraded to smaller fragments. We believe that this degradation is largely the result of the action of IDE, as it can be substantially blocked by the presence of insulin in the medium, a competitive substrate of IDE. No inhibition is seen when an inhibitor of neprilysin, another protease that may degrade Abeta, is present in the medium. Our evidence suggests that the action of IDE occurs outside the cell, as inhibitors of internalization fail to affect the rate of the observed degradation. Further, our evidence suggests that degradation by IDE occurs on the plasma membrane, as much of the IDE present in HCECs was biotin-labeled by a plasma membrane impermeable reagent. This activity seems to be polarity dependent, as measurement of Abeta degradation by each surface of differentiated HCECs shows greater degradation on the basolateral (brain-facing) surface. Thus, IDE could be an important therapeutic target to decrease the amount of Abeta in the cerebrovasculature.
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Affiliation(s)
- John A Lynch
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Goodman AB. Retinoid receptors, transporters, and metabolizers as therapeutic targets in late onset Alzheimer disease. J Cell Physiol 2006; 209:598-603. [PMID: 17001693 DOI: 10.1002/jcp.20784] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Vitamin A (retinoid) is required in the adult brain to enable cognition, learning, and memory. While brain levels of retinoid diminish over the course of normal ageing, retinoid deficit is greater in late onset Alzheimer disease (LOAD) brains than in normal-aged controls. This paper reviews recent evidence supporting these statements and further suggests that genes necessary for the synthesis, transport and function of retinoid to and within the ageing brain are appropriate targets for treatment of LOAD. These genes tend to be clustered with genes that have been proposed as candidates in LOAD, are found at chromosomal regions linked to LOAD, and suggest the possibility of an overall coordinated regulation. This phenomenon is termed Chromeron and is analogous to the operon mechanism observed in prokaryotes. Suggested treatment targets are the retinoic-acid inactivating enzymes (CYP26)s, the retinol binding and transport proteins, retinol-binding protein (RBP)4 and transthyretin (TTR), and the retinoid receptors. TTR as a LOAD target is the subject of active investigation. The retinoid receptors and the retinoid-inactivating enzymes have previously been proposed as targets. This is the first report to suggest that RBP4 is an amenable treatment target in LOAD. RBP4 is elevated in type-2 diabetes and obesity, conditions associated with increased risk for LOAD. Fenretinide, a novel synthetic retinoic acid (RA) analog lowers RBP4 in glucose intolerant obese mice. The feasibility of using fenretinide either as an adjunct to present LOAD therapies, or on its own as an early prevention strategy should be determined.
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Affiliation(s)
- Ann B Goodman
- The Massachusetts Mental Health Center Academic Division of Public Psychiatry, Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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Feuk L, McCarthy S, Andersson B, Prince JA, Brookes AJ. Mutation screening of a haplotype block around the insulin degrading enzyme gene and association with Alzheimer's disease. Am J Med Genet B Neuropsychiatr Genet 2005; 136B:69-71. [PMID: 15858821 DOI: 10.1002/ajmg.b.30172] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Genetic and biological studies point to a role for insulin-degrading enzyme (IDE) in Alzheimer's disease (AD). Two SNP-based studies recently reported evidence for association with AD using markers in a approximately 270 kb haplotype block on chromosome 10q. This haplotype block region harbors three known genes; insulin-degrading enzyme (IDE), kinesin family member 11 (KIF11), and hematopoietically expressed homeobox (HHEX). In an attempt to search for susceptibility variants we have sequenced all coding exons, 2 kb of 5' and 3'-flanking sequence, and all regions showing a high degree of human-mouse conservation in these three genes in 30 individuals. We found a total of 40 single nucleotide polymorphisms and 8 insertion/deletion polymorphisms. No coding variants were identified in any of the three genes. Nine polymorphisms in IDE and four polymorphisms in KIF11 situated in conserved regions or near coding exons were subsequently genotyped in a set of AD cases and controls. Two markers in KIF11 yielded borderline significant results in the ApoE4 non-carrier subgroup, but the results were otherwise not significant in this small set of samples. This study of multiple new markers in the region will facilitate further association studies in this important AD region.
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Affiliation(s)
- Lars Feuk
- Center for Genomics and Bioinformatics, Karolinska Institute, Stockholm, Sweden
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Genetics of Alzheimer's disease. NEURODEGENER DIS 2005. [DOI: 10.1017/cbo9780511544873.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Leissring M, Farris W, Wu X, Christodoulou D, Haigis M, Guarente L, Selkoe D. Alternative translation initiation generates a novel isoform of insulin-degrading enzyme targeted to mitochondria. Biochem J 2005; 383:439-46. [PMID: 15285718 PMCID: PMC1133736 DOI: 10.1042/bj20041081] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
IDE (insulin-degrading enzyme) is a widely expressed zinc-metallopeptidase that has been shown to regulate both cerebral amyloid beta-peptide and plasma insulin levels in vivo. Genetic linkage and allelic association have been reported between the IDE gene locus and both late-onset Alzheimer's disease and Type II diabetes mellitus, suggesting that altered IDE function may contribute to some cases of these highly prevalent disorders. Despite the potentially great importance of this peptidase to health and disease, many fundamental aspects of IDE biology remain unresolved. Here we identify a previously undescribed mitochondrial isoform of IDE generated by translation at an in-frame initiation codon 123 nucleotides upstream of the canonical translation start site, which results in the addition of a 41-amino-acid N-terminal mitochondrial targeting sequence. Fusion of this sequence to the N-terminus of green fluorescent protein directed this normally cytosolic protein to mitochondria, and full-length IDE constructs containing this sequence were also directed to mitochondria, as revealed by immuno-electron microscopy. Endogenous IDE protein was detected in purified mitochondria, where it was protected from digestion by trypsin and migrated at a size consistent with the predicted removal of the N-terminal targeting sequence upon transport into the mitochondrion. Functionally, we provide evidence that IDE can degrade cleaved mitochondrial targeting sequences. Our results identify new mechanisms regulating the subcellular localization of IDE and suggest previously unrecognized roles for IDE within mitochondria.
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Affiliation(s)
- Malcolm A. Leissring
- *Center for Neurologic Diseases, Department of Neurology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, U.S.A
| | - Wesley Farris
- *Center for Neurologic Diseases, Department of Neurology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, U.S.A
| | - Xining Wu
- *Center for Neurologic Diseases, Department of Neurology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, U.S.A
| | - Danos C. Christodoulou
- †Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A
| | - Marcia C. Haigis
- †Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A
| | - Leonard Guarente
- †Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A
| | - Dennis J. Selkoe
- *Center for Neurologic Diseases, Department of Neurology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, U.S.A
- To whom correspondence should be addressed: Harvard Institutes of Medicine, 77 Avenue Louis Pasteur, Boston, MA 02115, U.S.A. (email )
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Lee JH, Mayeux R, Mayo D, Mo J, Santana V, Williamson J, Flaquer A, Ciappa A, Rondon H, Estevez P, Lantigua R, Kawarai T, Toulina A, Medrano M, Torres M, Stern Y, Tycko B, Rogaeva E, George-Hyslop PS, Knowles JA. Fine mapping of 10q and 18q for familial Alzheimer's disease in Caribbean Hispanics. Mol Psychiatry 2004; 9:1042-51. [PMID: 15241431 PMCID: PMC1578737 DOI: 10.1038/sj.mp.4001538] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Familial Alzheimer's disease (AD [MIM 104300]) has been a focus of intense investigation, primarily in Caucasian families from Europe and North America families. Although the late-onset form of familial AD, beginning after age 65 years, has been linked to regions on chromosomes 10q and 12p, the specific genetic variants have not yet been consistently identified. Using a unique cohort of families of Caribbean Hispanics ancestry, we screened the genome using 340 markers on 490 family members from 96 families with predominantly late-onset AD. We observed the strongest support for linkage on 18q (LOD=3.14). However, 17 additional markers (chromosomes 1-6, 8, 10, 12, and 14) exceeded a two-point LOD score of 1.0 under the affecteds-only autosomal dominant model or affected sibpair model. As we previously reported the fine-mapping effort on 12p showing modest evidence of linkage, we focused our fine-mapping efforts on two other candidate regions in the current report, namely 10q and 18q. We added 31 family members and eight additional Caribbean Hispanic families to fine map 10q and 18q. With additional microsatellite markers, the evidence for linkage for 18q strengthened near 112 cM, where the two-point LOD score for D18S541 was 3.37 and the highest NPL score in that region was 3.65 (P=0.000177). This narrow region contains a small number of genes expressed in the brain. However, at 10q (134-138 cM), the NPL score decreased from 3.15 (P=0.000486) to 2.1 (P=0.0218), but two broad peaks remained overlapping with previously reported peaks. Our results provide modest support for linkage on 10q and 12p in this cohort of Caribbean Hispanic families with familial Alzheimer's disease, and strong evidence for a new locus on 18q.
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Affiliation(s)
- JH Lee
- The Taub Institute on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, USA
- The Gertrude H. Sergievsky Center, Columbia University, New York, USA
- Department of Epidemiology, School of Public Health, Columbia University, New York, USA
| | - R Mayeux
- The Taub Institute on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, USA
- The Gertrude H. Sergievsky Center, Columbia University, New York, USA
- Department of Neurology, College of Physicians Surgeons, Columbia University, New York, USA
- Department of Psychiatry, College of Physicians Surgeons, Columbia University, New York, USA
- Department of Epidemiology, School of Public Health, Columbia University, New York, USA
| | - D Mayo
- Department of Psychiatry, College of Physicians Surgeons, Columbia University, New York, USA
- The Columbia Genome Center, Columbia University, New York, USA
- The New York State Psychiatric Institute, New York, USA
| | - J Mo
- Department of Psychiatry, College of Physicians Surgeons, Columbia University, New York, USA
- The Columbia Genome Center, Columbia University, New York, USA
- The New York State Psychiatric Institute, New York, USA
| | - V Santana
- The Gertrude H. Sergievsky Center, Columbia University, New York, USA
| | - J Williamson
- The Taub Institute on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, USA
- The Gertrude H. Sergievsky Center, Columbia University, New York, USA
| | - A Flaquer
- The Taub Institute on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, USA
- The Gertrude H. Sergievsky Center, Columbia University, New York, USA
| | - A Ciappa
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, USA
| | - H Rondon
- The Gertrude H. Sergievsky Center, Columbia University, New York, USA
- The Plaza de la Salud Hospital, Dominican Republic
| | - P Estevez
- The Gertrude H. Sergievsky Center, Columbia University, New York, USA
| | - R Lantigua
- The Taub Institute on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, USA
- Department of Medicine, College of Physicians Surgeons, Columbia University, New York, USA
| | - T Kawarai
- Centre for Research in Neurodegenerative Diseases, University of Toronto and Department of Medicine, University Health Network, Toronto, Ontario, Canada
| | - A Toulina
- Centre for Research in Neurodegenerative Diseases, University of Toronto and Department of Medicine, University Health Network, Toronto, Ontario, Canada
| | - M Medrano
- The Universidad Tecnologica de Santiago, Dominican Republic
| | - M Torres
- The Plaza de la Salud Hospital, Dominican Republic
| | - Y Stern
- The Taub Institute on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, USA
- The Gertrude H. Sergievsky Center, Columbia University, New York, USA
- Department of Neurology, College of Physicians Surgeons, Columbia University, New York, USA
- Department of Psychiatry, College of Physicians Surgeons, Columbia University, New York, USA
| | - B Tycko
- The Taub Institute on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, USA
- Department of Pathology, College of Physicians and Surgeons, Columbia University, New York, USA
| | - E Rogaeva
- Centre for Research in Neurodegenerative Diseases, University of Toronto and Department of Medicine, University Health Network, Toronto, Ontario, Canada
| | - P St. George-Hyslop
- Centre for Research in Neurodegenerative Diseases, University of Toronto and Department of Medicine, University Health Network, Toronto, Ontario, Canada
| | - JA Knowles
- The Taub Institute on Alzheimer’s Disease and the Aging Brain, Columbia University, New York, USA
- Department of Psychiatry, College of Physicians Surgeons, Columbia University, New York, USA
- The Columbia Genome Center, Columbia University, New York, USA
- The New York State Psychiatric Institute, New York, USA
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14
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Gao W, Eisenhauer PB, Conn K, Lynch JA, Wells JM, Ullman MD, McKee A, Thatte HS, Fine RE. Insulin degrading enzyme is expressed in the human cerebrovascular endothelium and in cultured human cerebrovascular endothelial cells. Neurosci Lett 2004; 371:6-11. [PMID: 15500957 DOI: 10.1016/j.neulet.2004.07.034] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Revised: 07/09/2004] [Accepted: 07/10/2004] [Indexed: 10/26/2022]
Abstract
Insulin degrading enzyme (IDE) is found in the cytosol, peroxisomes and plasma membrane of many cells. Although it preferentially cleaves insulin it can also cleave many other small proteins with diverse sequences including the monomeric form of the amyloid beta peptide (A beta). In the brain, IDE has been reported to be expressed predominantly in neurons. In this study, IDE expression was detected in cultured human cerebrovascular endothelial cells. Using laser capture microdissection followed by PCR analysis, it was found that IDE mRNA is expressed in human brain blood vessels. Using immunofluorescence and multiphoton microscopy IDE was localized to the endothelium of the cerebrovascular blood vessels in human.
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Affiliation(s)
- Wenwu Gao
- ENR VA Medical Center, Bedford, MA 01730, USA
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15
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Edland SD. Insulin-degrading enzyme, apolipoprotein E, and Alzheimer's disease. J Mol Neurosci 2004; 23:213-7. [PMID: 15181249 DOI: 10.1385/jmn:23:3:213] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2003] [Accepted: 02/04/2004] [Indexed: 01/15/2023]
Abstract
Insulin-degrading enzyme (IDE) is a protease that degrades insulin and the beta-amyloid (Abeta) peptide implicated in Alzheimer's disease (AD). Hence, factors that influence IDE expression or IDE activity toward Abeta are potentially relevant to the etiology of AD. Hippocampal IDE mRNA levels are lower on average in subjects with an APOE epsilon4 allele, suggesting that the genetic risk conferred by APOE epsilon4 may be mediated in part by this allele's effect on IDE expression. Other factors that influence IDE may be relevant in non-epsilon4 carriers. For example, insulin, a competitive inhibitor of IDE activity toward Abeta, may be elevated in non-epsilon4 cases. We here report IDE gene promoter region variants that are associated with AD in subjects without an epsilon4 allele. If these promoter region variants prove to affect expression levels, they may be relevant to disease as well. Further investigation of the relationship between APOE genotype, IDE genetic variants, and the expression and activity of hippocampal IDE is warranted.
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Affiliation(s)
- Steven D Edland
- Mayo Clinic and Foundation Division of Clinical Epidemiology, Rochester, MN 55905, USA.
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16
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Ertekin-Taner N, Allen M, Fadale D, Scanlin L, Younkin L, Petersen RC, Graff-Radford N, Younkin SG. Genetic variants in a haplotype block spanning IDE are significantly associated with plasma Abeta42 levels and risk for Alzheimer disease. Hum Mutat 2004; 23:334-42. [PMID: 15024728 DOI: 10.1002/humu.20016] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Risk for late onset Alzheimer disease (LOAD) and plasma amyloid beta levels (Abeta42; encoded by APP), an intermediate phenotype for LOAD, show linkage to chromosome 10q. Several strong candidate genes (VR22, PLAU, IDE) lie within the 1-lod support interval for linkage. Others have independently identified haplotypes in the chromosome 10q region harboring IDE that show highly significant association with intermediate AD phenotypes and with risk for AD. To pursue these associations, we analyzed the same haplotypes for association with plasma Abeta42 in 24 extended LOAD families and for association with LOAD in two independent case-control series. One series (MCR, 188 age-matched case-control pairs) did not show association (p=0.64) with the six haplotypes in the 276-kb region spanning three genes (IDE, KNSL1, and HHEX) previously shown to associate with LOAD. The other series (MCJ, 109 age-matched case-control pairs) showed significant (p=0.003) association with these haplotypes. In the MCJ series, the H4 (odds ratio [OR]=5.1, p=0.003) and H2(H7) haplotypes (OR=0.60, p=0.04) had the same effects previously reported. In this series, the H8 haplotype (OR=2.7, p=0.098) also had an effect similar as in one previous case control series but not in others. In the extended families, the H8 haplotype was associated with significantly elevated plasma Abeta42 (p=0.02). In addition, the H5(H10) haplotype, which is associated with reduced risk for AD in the other study is associated with reduced plasma Abeta42 (p=0.007) in our family series. These results provide strong evidence for pathogenic variant(s) in the 276-kb region harboring IDE that influence intermediate AD phenotypes and risk for AD.
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17
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Farris W, Mansourian S, Leissring MA, Eckman EA, Bertram L, Eckman CB, Tanzi RE, Selkoe DJ. Partial loss-of-function mutations in insulin-degrading enzyme that induce diabetes also impair degradation of amyloid beta-protein. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 164:1425-34. [PMID: 15039230 PMCID: PMC1615329 DOI: 10.1016/s0002-9440(10)63229-4] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The causes of cerebral accumulation of amyloid beta-protein (Abeta) in most cases of Alzheimer's disease (AD) remain unknown. We recently found that homozygous deletion of the insulin-degrading enzyme (IDE) gene in mice results in an early and marked elevation of cerebral Abeta. Both genetic linkage and allelic association in the IDE region of chromosome 10 have been reported in families with late-onset AD. For IDE to remain a valid candidate gene for late-onset AD on functional grounds, it must be shown that partial loss of function of IDE can still alter Abeta degradation, but without causing early, severe elevation of brain Abeta. Here, we show that naturally occurring IDE missense mutations in a well-characterized rat model of type 2 diabetes mellitus (DM2) result in decreased catalytic efficiency and a significant approximately 15 to 30% deficit in the degradation of both insulin and Abeta. Endogenously secreted Abeta(40) and Abeta(42) are significantly elevated in primary neuronal cultures from animals with the IDE mutations, but there is no increase in steady-state levels of rodent Abeta in the brain up to age 14 months. We conclude that naturally occurring, partial loss-of-function mutations in IDE sufficient to cause DM2 also impair neuronal regulation of Abeta levels, but the brain can apparently compensate for the partial deficit during the life span of the rat. Our findings have relevance for the emerging genetic evidence suggesting that IDE may be a late-onset AD-risk gene, and for the epidemiological relationships among hyperinsulinemia, DM2, and AD.
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Affiliation(s)
- Wesley Farris
- Department of Neurology, Center for Neurologic Diseases, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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18
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Abstract
Insulin has functions in the brain and dysregulation of these functions may contribute to the expression of late-life neurodegenerative disease. We provide a brief summary of research on the influence of insulin on normal brain function. We then review evidence that perturbation of this role may contribute to the symptoms and pathogenesis of various neurodegenerative disorders, such as Alzheimer's disease, vascular dementia, Parkinson's disease, and Huntington's disease. We conclude by considering whether insulin dysregulation contributes to neurodegenerative disorders through disease-specific or general mechanisms.
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Affiliation(s)
- Suzanne Craft
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Puget Sound Medical Center, Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, 98108, USA.
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19
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Sakai A, Ujike H, Nakata K, Takehisa Y, Imamura T, Uchida N, Kanzaki A, Yamamoto M, Fujisawa Y, Okumura K, Kuroda S. No association between the insulin degrading enzyme gene and Alzheimer's disease in a Japanese population. Am J Med Genet B Neuropsychiatr Genet 2004; 125B:87-91. [PMID: 14755451 DOI: 10.1002/ajmg.b.20106] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Susceptibility to Alzheimer's disease (AD) is thought to be regulated by multiple genetic factors. Recently, three independent studies have reported that loci on chromosome 10q are linked with AD, and the insulin degrading enzyme (IDE; MIM 146680) gene located on chromosome 10q23-q25; IDE is located close to the maker D10S583, which exhibits a maximum LOD score for late-onset AD. We examined seven polymorphisms in the IDE gene, the marker D10S583 in the 5' flanking region, and SNPs in introns 1, 3, 11, 20, 21, and 22 (rs#1999764, 1855915, 1970244, 538469, 551266, and 489517, respectively). Four SNPs in introns 3, 11, 20, and 22 did not exhibit any polymorphisms in the Japanese population that was studied. D10S583 and two SNPs in introns 1 and 21 did not exhibit a significant association with early- or late-onset AD. In addition, no associations were observed for subgroups of AD grouped according to APOE status. The present study indicates that the IDE gene polymorphisms do not confer susceptibility to early- or late-onset AD at least in a Japanese population.
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20
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Leissring MA, Farris W, Chang AY, Walsh DM, Wu X, Sun X, Frosch MP, Selkoe DJ. Enhanced Proteolysis of β-Amyloid in APP Transgenic Mice Prevents Plaque Formation, Secondary Pathology, and Premature Death. Neuron 2003; 40:1087-93. [PMID: 14687544 DOI: 10.1016/s0896-6273(03)00787-6] [Citation(s) in RCA: 537] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Converging evidence suggests that the accumulation of cerebral amyloid beta-protein (Abeta) in Alzheimer's disease (AD) reflects an imbalance between the production and degradation of this self-aggregating peptide. Upregulation of proteases that degrade Abeta thus represents a novel therapeutic approach to lowering steady-state Abeta levels, but the consequences of sustained upregulation in vivo have not been studied. Here we show that transgenic overexpression of insulin-degrading enzyme (IDE) or neprilysin (NEP) in neurons significantly reduces brain Abeta levels, retards or completely prevents amyloid plaque formation and its associated cytopathology, and rescues the premature lethality present in amyloid precursor protein (APP) transgenic mice. Our findings demonstrate that chronic upregulation of Abeta-degrading proteases represents an efficacious therapeutic approach to combating Alzheimer-type pathology in vivo.
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Affiliation(s)
- Malcolm A Leissring
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Harvard Medical School, Boston, MA 02115, USA
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21
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Leissring MA, Lu A, Condron MM, Teplow DB, Stein RL, Farris W, Selkoe DJ. Kinetics of amyloid beta-protein degradation determined by novel fluorescence- and fluorescence polarization-based assays. J Biol Chem 2003; 278:37314-20. [PMID: 12867419 DOI: 10.1074/jbc.m305627200] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteases that degrade the amyloid beta-protein (Abeta) are important regulators of brain Abeta levels in health and in Alzheimer's disease, yet few practical methods exist to study their detailed kinetics. Here, we describe robust and quantitative Abeta degradation assays based on the novel substrate, fluorescein-Abeta-(1-40)-Lys-biotin (FAbetaB). Liquid chromatography/mass spectrometric analysis shows that FAbetaB is hydrolyzed at closely similar sites as wild-type Abeta by neprilysin and insulin-degrading enzyme, the two most widely studied Abeta-degrading proteases. The derivatized peptide is an avid substrate and is suitable for use with biological samples and in high throughput compound screening. The assays we have developed are easily implemented and are particularly useful for the generation of quantitative kinetic data, as we demonstrate by determining the kinetic parameters of FAbetaB degradation by several Abeta-degrading proteases, including plasmin, which has not previously been characterized. The use of these assays should yield additional new insights into the biology of Abeta-degrading proteases and facilitate the identification of activators and inhibitors of such enzymes.
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Affiliation(s)
- Malcolm A Leissring
- Center for Neurologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
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22
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Prince JA, Feuk L, Gu HF, Johansson B, Gatz M, Blennow K, Brookes AJ. Genetic variation in a haplotype block spanningIDE influences Alzheimer disease. Hum Mutat 2003; 22:363-71. [PMID: 14517947 DOI: 10.1002/humu.10282] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Linkage studies have identified a large (>60-Mb) region on chromosome 10q that segregates with Alzheimer Disease (AD). Within the region, the gene for insulin degrading enzyme (IDE) represents a notable biological candidate given that it degrades amyloid beta-protein (one of the major constituents of senile plaques) and the intracellular amyloid precursor protein (APP) domain released by gamma-secretase processing. We have used a single nucleotide polymorphism (SNP) genetic association strategy to investigate AD in relation to a 480-kb region encompassing IDE. A 276-kb linkage disequilibrium block was revealed that spans three genes (IDE, KNSL1, and HHEX). Assessing this block in several independent sets of case-control materials (early- and late-onset AD) and focusing also upon quantitative measures that are pertinent to AD diagnosis and severity (MMSE scores, microtubule-associated protein Tau [MAPT] levels in CSF, degree of brain pathology, and age-at-onset) produced extensive evidence for significant AD association. Signals (p-values ranging from 0.05 to <1x10(-9)) were generally stronger when examining haplotypes rather than individual SNPs, and quantitative trait tests most uniformly revealed the detected associations. Consistent risk alleles and haplotypes were apparent across the study, with effects in some cases as large as that of the epsilon4 allele of APOE. A subsequent mutation screen of exons in all three suspect genes provided no evidence for common causative mutations. These results provide substantial evidence that genetic variation within or extremely close to IDE impacts both disease risk and traits related to the severity of AD.
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Affiliation(s)
- Jonathan A Prince
- Center for Genomics and Bioinformatics, Karolinska Institute, Stockholm, Sweden
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23
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Edland SD, Wavrant-De Vriesé F, Compton D, Smith GE, Ivnik R, Boeve BF, Tangalos EG, Petersen RC. Insulin degrading enzyme (IDE) genetic variants and risk of Alzheimer's disease: evidence of effect modification by apolipoprotein E (APOE). Neurosci Lett 2003; 345:21-4. [PMID: 12809979 DOI: 10.1016/s0304-3940(03)00488-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Insulin degrading enzyme (IDE) is a protease that degrades insulin and the beta-amyloid peptide implicated in Alzheimer's disease (AD). We reexamined data on five previously reported IDE polymorphisms stratifying the analysis by the presence or absence of an apolipoprotein E (APOE) epsilon4 allele. Three IDE variants were associated with AD within epsilon4-negative subjects (genotype exact test P-values < or =0.02). A haplotype containing the minor variant at each of these sites represented an estimated 4.2% of case haplotypes versus 12.3% of control haplotypes among epsilon4-negative subjects. Lack of this minor haplotype may be predictive of AD, potentially explaining some fraction of disease within subjects without the APOE epsilon4 risk allele. Confirmation of this finding with a larger sample of cases and controls is warranted.
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Affiliation(s)
- S D Edland
- Division of Clinical Epidemiology, Mayo Clinic and Foundation, 200 First Street SW, Rochester, MN 55905, USA.
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24
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Farris W, Mansourian S, Chang Y, Lindsley L, Eckman EA, Frosch MP, Eckman CB, Tanzi RE, Selkoe DJ, Guenette S. Insulin-degrading enzyme regulates the levels of insulin, amyloid beta-protein, and the beta-amyloid precursor protein intracellular domain in vivo. Proc Natl Acad Sci U S A 2003; 100:4162-7. [PMID: 12634421 PMCID: PMC153065 DOI: 10.1073/pnas.0230450100] [Citation(s) in RCA: 1073] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Two substrates of insulin-degrading enzyme (IDE), amyloid beta-protein (Abeta) and insulin, are critically important in the pathogenesis of Alzheimer's disease (AD) and type 2 diabetes mellitus (DM2), respectively. We previously identified IDE as a principal regulator of Abeta levels in neuronal and microglial cells. A small chromosomal region containing a mutant IDE allele has been associated with hyperinsulinemia and glucose intolerance in a rat model of DM2. Human genetic studies have implicated the IDE region of chromosome 10 in both AD and DM2. To establish whether IDE hypofunction decreases Abeta and insulin degradation in vivo and chronically increases their levels, we characterized mice with homozygous deletions of the IDE gene (IDE --). IDE deficiency resulted in a >50% decrease in Abeta degradation in both brain membrane fractions and primary neuronal cultures and a similar deficit in insulin degradation in liver. The IDE -- mice showed increased cerebral accumulation of endogenous Abeta, a hallmark of AD, and had hyperinsulinemia and glucose intolerance, hallmarks of DM2. Moreover, the mice had elevated levels of the intracellular signaling domain of the beta-amyloid precursor protein, which was recently found to be degraded by IDE in vitro. Together with emerging genetic evidence, our in vivo findings suggest that IDE hypofunction may underlie or contribute to some forms of AD and DM2 and provide a mechanism for the recently recognized association among hyperinsulinemia, diabetes, and AD.
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Affiliation(s)
- Wesley Farris
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital, Boston, MA 02115, USA
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25
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Goodman AB, Pardee AB. Evidence for defective retinoid transport and function in late onset Alzheimer's disease. Proc Natl Acad Sci U S A 2003; 100:2901-5. [PMID: 12604774 PMCID: PMC151438 DOI: 10.1073/pnas.0437937100] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hypothesis of this article is that late onset Alzheimer's disease (AD) is influenced by the availability in brain of retinoic acid (RA), the final product of the vitamin A (retinoid) metabolic cascade. Genetic, metabolic, and environmental/dietary evidence is cited supporting this hypothesis. Significant genetic linkages to AD are demonstrated for markers close to four of the six RA receptors, RA receptor G at 12q13, retinoid X receptor B at 6p21.3, retinoid X receptor G at 1q21, and RA receptor A at 17q21. Three of the four retinol-binding proteins at 3q23 and 10q23 and the RA-degrading cytochrome P450 enzymes at 10q23 and 2p13 map to AD linkages. Synthesis of the evidence supports retinoid hypofunction and impaired transport as contributing factors. These findings suggest testable experiments to determine whether increasing the availability of retinoid in brain, possibly through pharmacologic targeting of the RA receptors and the cytochrome P450 RA-inactivating enzymes, can prevent or decrease amyloid plaque formation.
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MESH Headings
- Age of Onset
- Aging
- Alleles
- Alzheimer Disease/genetics
- Alzheimer Disease/metabolism
- Brain/metabolism
- Chromosome Mapping
- Chromosomes, Human, Pair 1
- Chromosomes, Human, Pair 10
- Chromosomes, Human, Pair 17
- Chromosomes, Human, Pair 2
- Chromosomes, Human, Pair 3
- Chromosomes, Human, Pair 6
- Genetic Linkage
- Humans
- Protein Transport
- Retinoids/metabolism
- Tretinoin/metabolism
- Up-Regulation
- Vitamin A/metabolism
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