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The Potential of Gonadal Hormone Signalling Pathways as Therapeutics for Dementia. J Mol Neurosci 2016; 60:336-348. [PMID: 27525638 DOI: 10.1007/s12031-016-0813-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/01/2016] [Indexed: 12/17/2022]
Abstract
Dementia is an ever-expanding problem facing an ageing society. Currently, there is a sharp paucity of treatment strategies. It has long been known that sex hormones, namely 17β-estradiol and testosterone, possess neuroprotective- and cognitive-enhancing qualities. However, certain lacunae in the knowledge underlying their molecular mechanisms have delayed their use as treatment strategies in dementia. With recent advancements in pharmacology and molecular biology, especially in the development of safer selective oestrogen receptor modulators and the recent discovery of the small-molecule brain-derived neurotrophic factor receptor agonist, 7,8-dihydroxyflavone, the exploitation of these signalling pathways for clinical use has become possible. This review aims to adumbrate the evidence and hurdles underscoring the use of sex hormones in the treatment of dementia as well as discussing some direction that is required to advance the translation of evidence into practise.
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Zhang F, Kang Z, Li W, Xiao Z, Zhou X. Roles of brain-derived neurotrophic factor/tropomyosin-related kinase B (BDNF/TrkB) signalling in Alzheimer's disease. J Clin Neurosci 2012; 19:946-9. [PMID: 22613489 DOI: 10.1016/j.jocn.2011.12.022] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 12/15/2011] [Accepted: 12/17/2011] [Indexed: 01/19/2023]
Abstract
Alzheimer's disease (AD) is one of the most common causes of dementia in the elderly. It is characterized by extracellular deposition of the neurotoxic peptide, amyloid-beta (Aβ) peptide fibrils, and is accompanied by extensive loss of neurons in the brains of affected individuals. However, the pathogenesis of AD is not fully understood. The aim of this review is to discuss the possible role of brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) signalling in the development of AD, focusing on BDNF/TrkB signalling in the production of Aβ, tau hyperphosphorylation and cognition decline, and exploring new possibilities for AD intervention.
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Affiliation(s)
- Fang Zhang
- Institute of Molecular and Clinical Medicine, Kunming Medical University, 1168, West Chunrong Road, Yuhua Street, Chenggong New Town, Kunming 650500, China.
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Ansaloni S, Leung BP, Sebastian NP, Samudralwar R, Gadaleta M, Saunders AJ. TrkB Isoforms Differentially Affect AICD Production through Their Intracellular Functional Domains. Int J Alzheimers Dis 2011; 2011:729382. [PMID: 21423675 PMCID: PMC3056454 DOI: 10.4061/2011/729382] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 11/12/2010] [Accepted: 11/16/2010] [Indexed: 12/30/2022] Open
Abstract
We report that NTRK2, the gene encoding for the TrkB receptor, can regulate APP metabolism, specifically AICD levels. Using the human neuroblastoma cell line SH-SY5Y, we characterized the effect of three TrkB isoforms (FL, SHC, T) on APP metabolism by knockdown and overexpression. We found that TrkB FL increases AICD-mediated transcription and APP levels while it decreases sAPP levels. These effects were mainly mediated by the tyrosine kinase activity of the receptor and partially by the PLC-γ- and SHC-binding sites. The TrkB T truncated isoform did not have significant effects on APP metabolism when transfected by itself, while the TrkB SHC decreased AICD-mediated transcription. TrkB T abolished TrkB FL effects on APP metabolism when cotransfected with it while TrkB SHC cotransfected with TrkB FL still showed increased APP levels. In conclusion, we demonstrated that TrkB isoforms have differential effects on APP metabolism.
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Affiliation(s)
- Sara Ansaloni
- Department of Biology, Drexel University, Philadelphia, PA 19027, USA
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Sherva R, Baldwin CT, Inzelberg R, Vardarajan B, Cupples LA, Lunetta K, Bowirrat A, Naj A, Pericak-Vance M, Friedland RP, Farrer LA. Identification of novel candidate genes for Alzheimer's disease by autozygosity mapping using genome wide SNP data. J Alzheimers Dis 2011; 23:349-59. [PMID: 21098978 PMCID: PMC3819807 DOI: 10.3233/jad-2010-100714] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Alzheimer's disease (AD) is highly prevalent in Wadi Ara despite the low frequency of apolipoprotein E ε4 in this genetically isolated Arab community in northern Israel. We hypothesized that the reduced genetic variability in combination with increased homozygosity would facilitate identification of genetic variants that contribute to the high rate of AD in this community. AD cases (n = 124) and controls (n = 142) from Wadi Ara were genotyped for a genome-wide set of more than 300,000 single nucleotides polymorphisms (SNPs) which were used to calculate measures of population stratification and inbreeding, and to identify regions of autozygosity. Although a high degree of relatedness was evident in both AD cases and controls, controls were significantly more related and contained more autozygous regions than AD cases (p = 0.004). Eight autozygous regions on seven different chromosomes were more frequent in controls than the AD cases, and 116 SNPs in these regions, primarily on chromosomes 2, 6, and 9, were nominally associated with AD. The association with rs3130283 in AGPAT1 on chromosome 6 was observed in a meta-analysis of seven genome-wide association study (GWAS) datasets. Analysis of the full Wadi Ara GWAS dataset revealed 220 SNP associations with AD at p ≤ 10⁻⁵, and seven of these were confirmed in the replication GWAS datasets (p < 0.05). The unique population structure of Wadi Ara enhanced efforts to identify genetic variants that might partially explain the high prevalence of AD in the region. Several of these variants show modest evidence for association in other Caucasian populations.
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Affiliation(s)
- Richard Sherva
- Department of Medicine (Genetics Program), Boston University School of Medicine, Boston, MA, USA
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Lee JH, Cheng R, Graff-Radford N, Foroud T, Mayeux R. Analyses of the National Institute on Aging Late-Onset Alzheimer's Disease Family Study: implication of additional loci. ACTA ACUST UNITED AC 2008; 65:1518-26. [PMID: 19001172 DOI: 10.1001/archneur.65.11.1518] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To identify putative genetic loci related to the risk of late-onset Alzheimer disease (LOAD). DESIGN Linkage analysis and family-based and case-control association analyses from a genomewide scan using approximately 6000 single-nucleotide polymorphic markers at an average intermarker distance of 0.65 cM. SETTING The National Institute on Aging Genetics Initiative for Late-Onset Alzheimer's Disease (NIA-LOAD) was created to expand the resources for studies to identify additional genes contributing to the risk for LOAD. PARTICIPANTS We investigated 1902 individuals from 328 families with LOAD and 236 unrelated control subjects. MAIN OUTCOME MEASURES Clinical diagnosis of LOAD. RESULTS The strongest overall finding was at chromosome 19q13.32, confirming the effect of the apolipoprotein E gene on LOAD risk in the family-based and case-control analyses. However, single-nucleotide polymorphisms at the following loci were also statistically significant in 1 or more of the analyses performed: 7p22.2, 7p21.3, and 16q21 in the linkage analyses; 17q21.31 and 22q11.21 in the family-based association analysis; and 7q31.1 and 22q12.3 in the case-control analysis. Positive associations at 7q31.1 and 20q13.33 were also significant in the meta-analysis results in a publicly available database. CONCLUSIONS Several additional loci may harbor genetic variants associated with LOAD. This data set provides a wealth of phenotypic and genotypic information for use as a resource in discovery and confirmatory research.
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Affiliation(s)
- Joseph H Lee
- Gertrude H. Sergievsky Center, Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Chen Z, Simmons MS, Perry RT, Wiener HW, Harrell LE, Go RCP. Genetic association of neurotrophic tyrosine kinase receptor type 2 (NTRK2) With Alzheimer's disease. Am J Med Genet B Neuropsychiatr Genet 2008; 147:363-9. [PMID: 17918233 DOI: 10.1002/ajmg.b.30607] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Brain-derived neurotrophic factor (BDNF)/tyrosine receptor kinase (TRK) signaling pathway activates a wide range of downstream intracellular cascades, regulating neuronal development and plasticity, long-term potentiation, and apoptosis. The NTRK family encodes the receptors TRKA, TRKB, and TRKC, to which the neurotrophins, nerve growth factor (NGF), BDNF and neurotrophin-3 (NT-3) bind, respectively, with high affinity. Signaling through these receptors appears to be compromised in Alzheimer's disease (AD). This study is the most comprehensive investigation of genetic variants of NTRK2, and the first to show significant association between NTRK2 with AD. Fourteen single nucleotide polymorphisms (SNPs), located in 8 of 18 linkage disequilibrium (LD) blocks, were genotyped in 203 families with at least two AD affected siblings with mean age of onset (MAO) of 70.9 +/- 7.4 years and one unaffected sibling from the NIMH-ADGJ dataset. Family based association testing found no single SNP association, however, significant associations were found for two and three locus haplotypes (P = 0.012, P = 0.009, respectively) containing SNPs rsl624327, rsl443445, and rs378645. These SNPs are located in areas of the gene containing sequences that could be involved in alternative splicing and/or regulation of NTRK2. Our results suggest that NTRK2 may be a genetic susceptibility gene contributing to AD pathology.
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Affiliation(s)
- Zuomin Chen
- Department of Epidemiology, University of Alabama at Birmingham School of Public Health, Birmingham, Alabama 35294, USA
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Hamshere ML, Holmans PA, Avramopoulos D, Bassett SS, Blacker D, Bertram L, Wiener H, Rochberg N, Tanzi RE, Myers A, Wavrant-De Vrièze F, Go R, Fallin D, Lovestone S, Hardy J, Goate A, O'Donovan M, Williams J, Owen MJ. Genome-wide linkage analysis of 723 affected relative pairs with late-onset Alzheimer's disease. Hum Mol Genet 2007; 16:2703-12. [PMID: 17725986 DOI: 10.1093/hmg/ddm224] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Previous attempts to identify genetic loci conferring risk for late-onset Alzheimer's disease (LOAD) through linkage analysis have observed some regions of linkage in common. However, due to the sometimes-considerable overlap between the samples, some of these reports cannot be considered to be independent replications. In order to assess the strength of the evidence for linkage and to obtain the best indication of the location of susceptibility genes, we have amalgamated three large samples to give a total of 723 affected relative pairs (ARPs). Multipoint, model-free ARP linkage analysis was performed. Genome-wide significant evidence for linkage was observed on 10q21.2 (LOD=3.3) and genome-wide suggestive evidence was observed on 9q22.33 (LOD=2.5) and 19q13.32 (LOD=2.0). One further region on 9p21.3 was identified with an LOD score>1. We observe no evidence to suggest that more than one locus is responsible for the linkage to 10q21.2, although this linked region may harbour more than one susceptibility gene. Evidence of allele-sharing heterogeneity between the original collection sites was observed on chromosome 9 but not on chromosome 10 or 19. Evidence for an interaction was observed between loci on chromosomes 10 and 19. Where samples overlapped, the genotyping consistency was high, estimated to average at 97.3%. Our large-scale linkage analysis consolidates clear evidence for a susceptibility locus for LOAD on 10q21.2.
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Affiliation(s)
- Marian L Hamshere
- Biostatistics and Bioinformatics Unit, School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, UK
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Arias-Vásquez A, de Lau L, Pardo L, Liu F, Feng BJ, Bertoli-Avella A, Isaacs A, Aulchenko Y, Hofman A, Oostra B, Breteler M, van Duijn C. Relationship of the Ubiquilin 1 gene with Alzheimer's and Parkinson's disease and cognitive function. Neurosci Lett 2007; 424:1-5. [PMID: 17709205 DOI: 10.1016/j.neulet.2007.07.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 07/06/2007] [Accepted: 07/06/2007] [Indexed: 12/18/2022]
Abstract
Ubiquilin 1 (UBQLN1) is involved in the ubiquitination machinery, which has been implicated in Alzheimer's disease (AD) as well as Parkinson's disease (PD). A polymorphism in the gene encoding for UBQLN1 has been previously associated with a higher risk of AD. We studied the role of the SNP rs12344615 on the UBQLN 1 gene in AD, PD and cognitive function in a population-based study, the Rotterdam Study, and a family-based study embedded in the genetic research in isolated population (GRIP) program. The Rotterdam Study includes 549 patients with AD and 157 patients with PD. The GRIP program includes a series of 123 patients with AD and a study of 1049 persons who are characterized for cognitive function. Data were analysed using logistic and multiple regression analysis. We found no significant difference in risk of AD or PD by the UBQLN1 SNP rs12344615 in our overall and stratified analyses in the Rotterdam Study. In our family-based study, we did not find evidence for linkage of AD to the region including the UBQLN1 gene. In the family-based study we also failed to detect an effect of this polymorphism on cognitive function. Our results suggest that it is unlikely that the SNP rs12344615 of the UBQLN1 gene is related to the onset of AD, PD or cognitive function.
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Ford DL, Monteiro MJ. Studies of the role of ubiquitination in the interaction of ubiquilin with the loop and carboxyl terminal regions of presenilin-2. Biochemistry 2007; 46:8827-37. [PMID: 17614368 PMCID: PMC2547082 DOI: 10.1021/bi700604q] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ubiquilin was originally identified as a presenilin-interacting protein. We previously reported that ubiquilin interacts with both the loop and carboxyl terminus of presenilin proteins and that the ubiquitin-associated (UBA) domain of ubiquilin, which binds poly ubiquitin chains, is important for mediating this interaction. In the present study, we examined whether ubiquitination of presenilin-2 (PS2) is required for interaction with ubiquilin-1 by mutating lysine residues that may be targets for ubiquitination in the presenilin loop and carboxyl terminus regions. Mutation of two lysine residues in the PS2-loop region suggested that ubiquitination is not required for interaction with ubiquilin-1 and may, in fact, even negatively regulate the interaction. Similarly, we found that ubiquitination of the PS2 carboxyl terminus (PS2-C-terminus) is not required for interaction with ubiquilin-1, although our results suggest that it could play some role. Instead, we found that the mutation of either one of the two lysine residues in the carboxyl terminus of PS2 or the proline residues in the highly conserved PALP motif in this region results in destabilization of the mutant PS2 polypeptides because of increased degradation by the proteasome. Furthermore, by GST-pull-down assays we found that the mutant polypeptides were unable to bind ubiquilin, suggesting that loss of ubiquilin interaction leads to destabilization of presenilin polypeptides. Paradoxically, however, knockdown of ubiquilin expression by RNA interference did not alter the rate of turnover of PS2 proteins in cells. Instead, we found that PS2 synthesis was reduced, and PS2 fragment production was increased, suggesting that ubiquilin expression modulates biogenesis and endoproteolysis of presenilin proteins.
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Affiliation(s)
- Diana L. Ford
- Medical Biotechnology Center, Program in Neurodegenerative Diseases, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, Maryland 21201
- Biochemistry and Molecular Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, Maryland 21201
| | - Mervyn J. Monteiro
- Medical Biotechnology Center, Program in Neurodegenerative Diseases, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, Maryland 21201
- Biochemistry and Molecular Biology Graduate Program, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, Maryland 21201
- Corresponding author: Mervyn J. Monteiro, Medical Biotechnology Center, Room N352, 725 West Lombard Street, Baltimore, MD 21201, Tel: 410-706-8132, Fax: 410-706-8184,
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Wang H, Monteiro MJ. Ubiquilin overexpression reduces GFP-polyalanine-induced protein aggregates and toxicity. Exp Cell Res 2007; 313:2810-20. [PMID: 17490645 PMCID: PMC2002572 DOI: 10.1016/j.yexcr.2007.04.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2007] [Revised: 03/11/2007] [Accepted: 04/03/2007] [Indexed: 10/23/2022]
Abstract
Several human disorders are associated with an increase in a continuous stretch of alanine amino acids in proteins. These so-called polyalanine expansion diseases share many similarities with polyglutamine-related disorders, including a length-dependent reiteration of amino acid induction of protein aggregation and cytotoxicity. We previously reported that overexpression of ubiquilin reduces protein aggregates and toxicity of expanded polyglutamine proteins. Here, we demonstrate a similar role for ubiquilin toward expanded polyalanine proteins. Overexpression of ubiquilin-1 in HeLa cells reduced protein aggregates and the cytotoxicity associated with expression of a transfected nuclear-targeted GFP-fusion protein containing 37-alanine repeats (GFP-A37), in a dose dependent manner. Ubiquilin coimmunoprecipitated more with GFP proteins containing a 37-polyalanine tract compared to either 7 (GFP-A7), or no alanine tract (GFP). Moreover, overexpression of ubiquilin suppressed the increased vulnerability of HeLa cell lines stably expressing the GFP-A37 fusion protein to oxidative stress-induced cell death compared to cell lines expressing GFP or GFP-A7 proteins. By contrast, siRNA knockdown of ubiquilin expression in the GFP-A37 cell line was associated with decreased cellular proliferation, and increases in GFP protein aggregates, nuclear fragmentation, and cell death. Our results suggest that boosting ubiquilin levels in cells might provide a universal and attractive strategy to prevent toxicity of proteins containing reiterative expansions of amino acids involved in many human diseases.
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Affiliation(s)
- Hongmin Wang
- Medical Biotechnology Center, Institute for Neurodegenerative Diseases, University of Maryland Biotechnology Institute, Room N352, Baltimore, MD 21201, USA
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