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Jellinger KA, Korczyn AD. Are dementia with Lewy bodies and Parkinson's disease dementia the same disease? BMC Med 2018; 16:34. [PMID: 29510692 PMCID: PMC5840831 DOI: 10.1186/s12916-018-1016-8] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/30/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), which share many clinical, neurochemical, and morphological features, have been incorporated into DSM-5 as two separate entities of major neurocognitive disorders with Lewy bodies. Despite clinical overlap, their diagnosis is based on an arbitrary distinction concerning the time of onset of motor and cognitive symptoms, namely as early cognitive impairment in DLB and later onset following that of motor symptoms in PDD. Their morphological hallmarks - cortical and subcortical α-synuclein/Lewy body plus β-amyloid and tau pathologies - are similar, but clinical differences at onset suggest some dissimilar profiles. Based on recent publications, including the fourth consensus report of the DLB Consortium, a critical overview is provided herein. DISCUSSION The clinical constellations of DLB and PDD include cognitive impairment, parkinsonism, visual hallucinations, and fluctuating attention. Intravitam PET and postmortem studies have revealed a more pronounced cortical atrophy, elevated cortical and limbic Lewy body pathologies, higher Aβ and tau loads in cortex and striatum in DLB compared to PDD, and earlier cognitive defects in DLB. Conversely, multitracer PET studies have shown no differences in cortical and striatal cholinergic and dopaminergic deficits. Clinical management of both DLB and PDD includes cholinesterase inhibitors and other pharmacologic and non-drug strategies, yet with only mild symptomatic effects. Currently, no disease-modifying therapies are available. CONCLUSION DLB and PDD are important dementia syndromes that overlap in many clinical features, genetics, neuropathology, and management. They are currently considered as subtypes of an α-synuclein-associated disease spectrum (Lewy body diseases), from incidental Lewy body disease and non-demented Parkinson's disease to PDD, DLB, and DLB with Alzheimer's disease at the most severe end. Cognitive impairment in these disorders is induced not only by α-synuclein-related neurodegeneration but by multiple regional pathological scores. Both DLB and PDD show heterogeneous pathology and neurochemistry, suggesting that they share important common underlying molecular pathogenesis with Alzheimer's disease and other proteinopathies. While we prefer to view DLB and PDD as extremes on a continuum, there remains a pressing need to more clearly differentiate these syndromes and to understand the synucleinopathy processes leading to either one.
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Affiliation(s)
- Kurt A Jellinger
- Institute of Clinical Neurobiology, Alberichgasse 5/13, A-1150, Vienna, Austria.
| | - Amos D Korczyn
- Tel-Aviv University, Sackler Faculty of Medicine, Ramat Aviv, Israel
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Cold-Inducible Protein RBM3 Protects UV Irradiation-Induced Apoptosis in Neuroblastoma Cells by Affecting p38 and JNK Pathways and Bcl2 Family Proteins. J Mol Neurosci 2017; 63:142-151. [DOI: 10.1007/s12031-017-0964-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/10/2017] [Indexed: 12/24/2022]
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Abstract
Dementia is a frequent problem encountered in advanced stages of Parkinson disease (PD). In recent years, research has focused on the pre-dementia stages of cognitive impairment in PD, including mild cognitive impairment (MCI). Several longitudinal studies have shown that MCI is a harbinger of dementia in PD, although the course is variable, and stabilization of cognition - or even reversal to normal cognition - is not uncommon. In addition to limbic and cortical spread of Lewy pathology, several other mechanisms are likely to contribute to cognitive decline in PD, and a variety of biomarker studies, some using novel structural and functional imaging techniques, have documented in vivo brain changes associated with cognitive impairment. The evidence consistently suggests that low cerebrospinal fluid levels of amyloid-β42, a marker of comorbid Alzheimer disease (AD), predict future cognitive decline and dementia in PD. Emerging genetic evidence indicates that in addition to the APOE*ε4 allele (an established risk factor for AD), GBA mutations and SCNA mutations and triplications are associated with cognitive decline in PD, whereas the findings are mixed for MAPT polymorphisms. Cognitive enhancing medications have some effect in PD dementia, but no convincing evidence that progression from MCI to dementia can be delayed or prevented is available, although cognitive training has shown promising results.
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Zhang T, Jia Y. Meta-analysis of Ubiquilin1 gene polymorphism and Alzheimer's disease risk. Med Sci Monit 2014; 20:2250-5. [PMID: 25387430 PMCID: PMC4238758 DOI: 10.12659/msm.891030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Some studies have evaluated the association between the Ubiquilin 1 (UBQLN1) gene UBQ-8i polymorphism and Alzheimer's disease (AD). However, the results remain uncertain. We carried out a meta-analysis to derive a more comprehensive estimation of this association. MATERIAL/METHODS Case-control studies were identified by searching databases of PubMed, EMBASE, Web of Science, CNKI, CBM, Wanfang, and VIP. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of the association. RESULTS The UBQ-8i polymorphism was significantly associated with an increased AD risk (OR=1.15; 95%CI 1.05-1.25; P=0.002). The combination of adjusted ORs also found UBQ-8i polymorphism was significantly associated with AD risk (OR=1.15; 95%CI 1.02-1.30; P=0.02). When stratified by APOE ε4 status, both APOE ε4 carriers and APOE non-ε4 carriers with UBQ-8i polymorphism had significantly increased AD risk (OR=1.28; 95%CI 1.05-1.56; P=0.01 and OR=1.25; 95%CI 1.04-1.50; P=0.02). In the subgroup analysis according to age, UBQ-8i polymorphism was significantly associated with LOAD risk (OR=1.17; 95%CI 1.05-1.31; P=0.005), but not with EOAD risk (OR=1.12; 95%CI 0.95-1.31; P=0.17). CONCLUSIONS These results suggest that the UBQ-8i polymorphism is associated with AD risk.
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Affiliation(s)
- Tianpeng Zhang
- Department of Integrated TCM & Western Medicine, People's Hospital, Hegang City, China (mainland)
| | - Yingying Jia
- Department of Neurosurgery, People's Hospital, Hegang City, China (mainland)
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Yue Z, Wang S, Yan W, Zhu F. Association of UBQ-8i polymorphism with Alzheimer's disease in Caucasians: a meta-analysis. Int J Neurosci 2014; 125:395-401. [PMID: 25010605 DOI: 10.3109/00207454.2014.943369] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Several studies have reported an association between the UBQ-8i (rs12344615) polymorphism of the UBQLN1 gene and risk of Alzheimer's disease (AD), but these findings remain controversial. In this study, a meta-analysis was carried out to investigate the relationship between UBQ-8i polymorphism and AD risk and a possible synergy with apolipoprotein E (APOE)ε4 gene status. METHODS Case-control studies were selected from PubMed, Medline and Embase (Ovid) databases. The potential association was evaluated by odds ratios (ORs) with 95% confidence intervals (CIs). Data were analyzed with Stata version 11.0. RESULTS A total of 4679 AD cases and 9928 controls were included in the study. There was no evidence of heterogeneity between studies or publication bias in the meta-analysis. There were no significant differences among the examined genetic models. In the analysis stratified by age of onset, a significant association was detected in the late onset AD group under the allele (OR = 1.12, 95% CI: 1.01-1.24), heterozygote (OR = 1.15, 95% CI: 1.02-1.30) and dominant (OR = 1.13, 95% CI: 1.00-1-26) models. However, UBQ-8i polymorphism was not associated with a higher risk for AD among APOEε4 carriers. CONCLUSION The results suggest that UBQ-8i polymorphism may contribute to AD susceptibility, but does not synergize with APOEε4 status to increase AD risk.
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Affiliation(s)
- Zhen Yue
- 1Department of Neurosurgery, First Affiliated Hospital of Nanjing Medical University , Nanjing , China
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Shah PP, Lockwood WW, Saurabh K, Kurlawala Z, Shannon SP, Waigel S, Zacharias W, Beverly LJ. Ubiquilin1 represses migration and epithelial-to-mesenchymal transition of human non-small cell lung cancer cells. Oncogene 2014; 34:1709-17. [PMID: 24747970 PMCID: PMC4205225 DOI: 10.1038/onc.2014.97] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 03/10/2014] [Accepted: 03/10/2014] [Indexed: 02/06/2023]
Abstract
Ubiquilin1 (UBQLN1) is a ubiquitin-like domain and a ubiquitin-associated domain containing protein that has been reported to be involved in shuttling proteins to the proteasome, especially during endoplasmic reticulum-associated protein degradation (ERAD). Thus, UBQLN1 function has been shown to be critical for combating a number of neurological disorders caused by protein aggregation, such as Amyotrophic lateral sclerosis (ALS), Alzheimer’s disease and Huntington’s disease. A role for UBQLN1 in regulating processes involved in tumorigenesis has not been demonstrated. Herein, we show that loss of UBQLN1 causes increased cell migration and invasion, actin cytoskeleton reorganization and induction of epithelial mesenchymal transition (EMT). Loss of UBQLN1 results in a significant decrease in the expression of epithelial markers including E-cadherin and claudin1, whereas expression of mesenchymal markers including Vimentin, Snail and ZEB1 are significantly elevated. Interestingly, we found that ZEB1 is required for induction of mesenchymal-like properties following loss of UBQLN1 and ZEB1 is capable of repressing expression of UBQLN1, suggesting a physiological, reciprocal regulation of EMT by UBQLN1 and ZEB1. Further, we find evidence for a role for UBQLN2 in also regulating EMT and cell migration. These observations have potential clinical relevance because the UBQLN1 gene is lost and under-expressed in a large percentage of human cancer cell lines and primary human lung cancer samples and recurrent mutations in both all five Ubiquilin family members have been identified in human lung cancers. Taken together, our results suggest for the first time a role for Ubiquilin family members in cancer biology.
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Affiliation(s)
- P P Shah
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA
| | - W W Lockwood
- Cancer Biology and Genetics Section, Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - K Saurabh
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA
| | - Z Kurlawala
- 1] James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA [2] Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA
| | - S P Shannon
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA
| | - S Waigel
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA
| | - W Zacharias
- 1] James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA [2] Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA [3] Division of Hematology and Oncology, Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA
| | - L J Beverly
- 1] James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA [2] Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, USA [3] Division of Hematology and Oncology, Department of Medicine, University of Louisville School of Medicine, Louisville, KY, USA
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The ubiquilin gene family: evolutionary patterns and functional insights. BMC Evol Biol 2014; 14:63. [PMID: 24674348 PMCID: PMC4230246 DOI: 10.1186/1471-2148-14-63] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 03/17/2014] [Indexed: 12/12/2022] Open
Abstract
Background Ubiquilins are proteins that function as ubiquitin receptors in eukaryotes. Mutations in two ubiquilin-encoding genes have been linked to the genesis of neurodegenerative diseases. However, ubiquilin functions are still poorly understood. Results In this study, evolutionary and functional data are combined to determine the origin and diversification of the ubiquilin gene family and to characterize novel potential roles of ubiquilins in mammalian species, including humans. The analysis of more than six hundred sequences allowed characterizing ubiquilin diversity in all the main eukaryotic groups. Many organisms (e. g. fungi, many animals) have single ubiquilin genes, but duplications in animal, plant, alveolate and excavate species are described. Seven different ubiquilins have been detected in vertebrates. Two of them, here called UBQLN5 and UBQLN6, had not been hitherto described. Significantly, marsupial and eutherian mammals have the most complex ubiquilin gene families, composed of up to 6 genes. This exceptional mammalian-specific expansion is the result of the recent emergence of four new genes, three of them (UBQLN3, UBQLN5 and UBQLNL) with precise testis-specific expression patterns that indicate roles in the postmeiotic stages of spermatogenesis. A gene with related features has independently arisen in species of the Drosophila genus. Positive selection acting on some mammalian ubiquilins has been detected. Conclusions The ubiquilin gene family is highly conserved in eukaryotes. The infrequent lineage-specific amplifications observed may be linked to the emergence of novel functions in particular tissues.
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Takalo M, Haapasalo A, Natunen T, Viswanathan J, Kurkinen KM, Tanzi RE, Soininen H, Hiltunen M. Targeting ubiquilin-1 in Alzheimer's disease. Expert Opin Ther Targets 2013; 17:795-810. [PMID: 23600477 DOI: 10.1517/14728222.2013.791284] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
INTRODUCTION Alzheimer's disease (AD) is a common neurodegenerative disorder affecting an increasing number of people worldwide as the population ages. Currently, there are no drugs available that could prevent AD pathogenesis or slow down its progression. Increasing evidence links ubiquilin-1, an ubiquitin-like protein, into the pathogenic mechanisms of AD and other neurodegenerative diseases. Ubiquilin-1 has been shown to play a key role in the regulation of the levels, subcellular targeting, aggregation and degradation of various neurodegenerative disease-associated proteins. These include the amyloid precursor protein and presenilins that are intimately involved in the mechanisms of AD. AREAS COVERED Here, the properties and diverse functions of ubiquilin-1 protein in the context of the pathogenesis of AD and other neurodegenerative disorders are discussed. This review recapitulates the available knowledge on the involvement of ubiquilin-1 in the genetic and molecular mechanisms in AD. Furthermore, the association of ubiquilin-1 with specific proteins and mechanisms involved in the pathogenesis of neurodegenerative diseases is described and the known ubiquilin-1-interacting proteins summarized. EXPERT OPINION The variety of ubiquilin-1-interacting proteins and its central role in the regulation of protein levels and degradation provides a number of novel candidates and approaches for future research and drug discovery.
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Affiliation(s)
- Mari Takalo
- Institute of Clinical Medicine-Neurology, University of Eastern Finland and Department of Neurology, Kuopio University Hospital, Kuopio, Finland
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El Ayadi A, Stieren ES, Barral JM, Boehning D. Ubiquilin-1 and protein quality control in Alzheimer disease. Prion 2013; 7:164-9. [PMID: 23360761 PMCID: PMC3609125 DOI: 10.4161/pri.23711] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Single nucleotide polymorphisms in the ubiquilin-1 gene may confer risk for late-onset Alzheimer disease (AD). We have shown previously that ubiquilin-1 functions as a molecular chaperone for the amyloid precursor protein (APP) and that protein levels of ubiquilin-1 are decreased in the brains of AD patients. We have recently found that ubiquilin-1 regulates APP trafficking and subsequent secretase processing by stimulating non-degradative ubiquitination of a single lysine residue in the cytosolic domain of APP. Thus, ubiquilin-1 plays a central role in regulating APP biosynthesis, trafficking and ultimately toxicity. As ubiquilin-1 and other ubiquilin family members have now been implicated in the pathogenesis of numerous neurodegenerative diseases, these findings provide mechanistic insights into the central role of ubiquilin proteins in maintaining neuronal proteostasis.
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Affiliation(s)
- Amina El Ayadi
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX USA
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Stieren ES, El Ayadi A, Xiao Y, Siller E, Landsverk ML, Oberhauser AF, Barral JM, Boehning D. Ubiquilin-1 is a molecular chaperone for the amyloid precursor protein. J Biol Chem 2011; 286:35689-35698. [PMID: 21852239 DOI: 10.1074/jbc.m111.243147] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alzheimer disease (AD) is associated with extracellular deposition of proteolytic fragments of amyloid precursor protein (APP). Although mutations in APP and proteases that mediate its processing are known to result in familial, early onset forms of AD, the mechanisms underlying the more common sporadic, yet genetically complex forms of the disease are still unclear. Four single-nucleotide polymorphisms within the ubiquilin-1 gene have been shown to be genetically associated with AD, implicating its gene product in the pathogenesis of late onset AD. However, genetic linkage between ubiquilin-1 and AD has not been confirmed in studies examining different populations. Here we show that regardless of genotype, ubiquilin-1 protein levels are significantly decreased in late onset AD patient brains, suggesting that diminished ubiquilin function may be a common denominator in AD progression. Our interrogation of putative ubiquilin-1 activities based on sequence similarities to proteins involved in cellular quality control showed that ubiquilin-1 can be biochemically defined as a bona fide molecular chaperone and that this activity is capable of preventing the aggregation of amyloid precursor protein both in vitro and in live neurons. Furthermore, we show that reduced activity of ubiquilin-1 results in augmented production of pathogenic amyloid precursor protein fragments as well as increased neuronal death. Our results support the notion that ubiquilin-1 chaperone activity is necessary to regulate the production of APP and its fragments and that diminished ubiquilin-1 levels may contribute to AD pathogenesis.
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Affiliation(s)
- Emily S Stieren
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Amina El Ayadi
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Yao Xiao
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Efraín Siller
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | - Megan L Landsverk
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Andres F Oberhauser
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555
| | - José M Barral
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas 77555.
| | - Darren Boehning
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555; Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas 77555; Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, Galveston, Texas 77555.
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11
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Chuo LJ, Wu ST, Chang HI, Kuo YM. Extremely rare incidence of the UBQLN1 polymorphism (UBQ-8i) in Taiwan Chinese with Alzheimer's disease. Neurosci Lett 2010; 475:108-9. [PMID: 20350585 DOI: 10.1016/j.neulet.2010.03.061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 03/17/2010] [Accepted: 03/22/2010] [Indexed: 11/30/2022]
Abstract
Recently, a single nucleotide polymorphism (SNP, A-->G) in intron 8 of UBQLN 1 at the rs12344615 site (UBQ-8i) on chromosome 9q22 was associated with a higher risk of late-onset Alzheimer's disease (AD). Here, we aimed to investigate whether an association exists between the UBQ-8i polymorphism and AD in Taiwan Chinese. Initially, we included 100 late-onset AD patients and 100 gender- and age-matched non-demented (ND) control participants. The UBQ-8i polymorphism site was successfully determined in 91 AD and 96 ND individuals using the dye terminator nucleotide sequencing technique. Among the 187 participants, we did not detect any subject carrying the G allele. This finding is in agreement with the report listed in the NCBI SNP Reference Assembly, which states that <1% of Asians carry this SNP. The APOE varepsilon4 allele, an established AD genetic risk factor, was overrepresented in the AD cohort. We conclude from these results that the UBQ-8i polymorphism of the UBQLN1 gene is extremely rare in Taiwan Chinese and unlikely to play a significant role in the risk of AD in Taiwan Chinese.
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Affiliation(s)
- Liang-Jen Chuo
- Department of Psychiatry, Taichung Veterans General Hospital, Taichung, Taiwan
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12
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Emerging role of Alzheimer's disease-associated ubiquilin-1 in protein aggregation. Biochem Soc Trans 2010; 38:150-5. [PMID: 20074050 DOI: 10.1042/bst0380150] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Abnormal protein aggregation and intracellular or extracellular accumulation of misfolded and aggregated proteins are key events in the pathogenesis of different neurodegenerative diseases. Furthermore, endoplasmic reticulum stress and impairment of the ubiquitin-proteasome system probably contribute to neurodegeneration in these diseases. A characteristic feature of AD (Alzheimer's disease) is the abnormal accumulation of Abeta (amyloid beta-peptide) in the brain. Evidence shows that the AD-associated PS (presenilin) also forms aggregates under certain conditions and that another AD-associated protein, ubiquilin-1, controls protein aggregation and deposition of aggregated proteins. Here, we review the current knowledge of ubiquilin-1 and PS in protein aggregation and related events that potentially influence neurodegeneration.
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Caccamo A, Majumder S, Deng JJ, Bai Y, Thornton FB, Oddo S. Rapamycin rescues TDP-43 mislocalization and the associated low molecular mass neurofilament instability. J Biol Chem 2009; 284:27416-24. [PMID: 19651785 DOI: 10.1074/jbc.m109.031278] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
TDP-43 is a nuclear protein involved in exon skipping and alternative splicing. Recently, TDP-43 has been identified as the pathological signature protein in frontotemporal lobar degeneration with ubiquitin-positive inclusions and in amyotrophic lateral sclerosis. In addition, TDP-43-positive inclusions are present in Parkinson disease, dementia with Lewy bodies, and 30% of Alzheimer disease cases. Pathological TDP-43 is redistributed from the nucleus to the cytoplasm, where it accumulates. An approximately 25-kDa C-terminal fragment of TDP-43 accumulates in affected brain regions, suggesting that it may be involved in the disease pathogenesis. Here, we show that overexpression of the 25-kDa C-terminal fragment is sufficient to cause the mislocalization and cytoplasmic accumulation of endogenous full-length TDP-43 in two different cell lines, thus recapitulating a key biochemical characteristic of TDP-43 proteinopathies. We also found that TDP-43 mislocalization is associated with a reduction in the low molecular mass neurofilament mRNA levels. Notably, we show that the autophagic system plays a role in TDP-43 metabolism. Specifically, we found that autophagy inhibition increases the accumulation of the C-terminal fragments of TDP-43, whereas inhibition of mTOR, a key protein kinase involved in autophagy regulation, reduces the 25-kDa C-terminal fragment accumulation and restores TDP-43 localization. Our results suggest that autophagy induction may be a valid therapeutic target for TDP-43 proteinopathies.
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Affiliation(s)
- Antonella Caccamo
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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14
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Current world literature. Trauma and rehabilitation. Curr Opin Neurol 2008; 21:762-4. [PMID: 18989123 DOI: 10.1097/wco.0b013e32831cbb85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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15
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Golan MP, Melquist S, Safranow K, Styczyńska M, Słowik A, Kobryś M, Zekanowski C, Barcikowska M. Analysis of UBQLN1 variants in a Polish Alzheimer's disease patient: control series. Dement Geriatr Cogn Disord 2008; 25:366-71. [PMID: 18340109 DOI: 10.1159/000121006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/09/2008] [Indexed: 11/19/2022] Open
Abstract
Late-onset Alzheimer's disease (LOAD) is the most common neurodegenerative disorder, and has a complex etiology. Recently an intronic polymorphism in the ubiquilin 1 gene (UBQLN1) and a particular haplotype was reported to be associated with LOAD. We investigated whether variants in UBQLN1 confer a risk for the disease in 407 Polish LOAD patients and 407 controls. We observed a weak association with the rs2781002 polymorphism, however, contrary to the initial reports, in our group the association was with the A allele. Risk estimation for AA versus GG genotypes showed that the AA genotype is a weak risk factor for AD (OR = 1.8, 95% CI = 1.1-3.1, p = 0.025). This effect was stronger in a group of LOAD patients without APOE4 allele. Haplotype analyses indicate that there is an increase of haplotypes with an A allele in the case group. Also, the specific haplotypes with the A allele that increase AD risk differ between the APOE4-positive and APOE4-negative pools. However, the association observed seems to be driven mostly by rare (<5%) haplotypes. Results suggest a need for additional association studies and in silico analysis of the UBQLN1 locus.
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Affiliation(s)
- Maciej P Golan
- Department of Neurodegenerative Disorders, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
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