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Kretzschmar GC, Alencar NM, da Silva SSL, Sulzbach CD, Meissner CG, Petzl-Erler ML, Souza RLR, Boldt ABW. GWAS-Top Polymorphisms Associated With Late-Onset Alzheimer Disease in Brazil: Pointing Out Possible New Culprits Among Non-Coding RNAs. Front Mol Biosci 2021; 8:632314. [PMID: 34291080 PMCID: PMC8287568 DOI: 10.3389/fmolb.2021.632314] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 05/31/2021] [Indexed: 01/06/2023] Open
Abstract
Several genome-wide association studies (GWAS) have been carried out with late-onset Alzheimer's disease (LOAD), mainly in European and Asian populations. Different polymorphisms were associated, but several of them without a functional explanation. GWAS are fundamental for identifying loci associated with diseases, although they often do not point to causal polymorphisms. In this sense, functional investigations are a fundamental tool for discovering causality, although the failure of this validation does not necessarily indicate a non-causality. Furthermore, the allele frequency of associated genetic variants may vary widely between populations, requiring replication of these associations in other ethnicities. In this sense, our study sought to replicate in 150 AD patients and 114 elderly controls from the South Brazilian population 18 single-nucleotide polymorphisms (SNPs) associated with AD in European GWAS, with further functional investigation using bioinformatic tools for the associated SNPs. Of the 18 SNPs investigated, only four were associated in our population: rs769449 (APOE), rs10838725 (CELF1), rs6733839, and rs744373 (BIN1-CYP27C1). We identified 54 variants in linkage disequilibrium (LD) with the associated SNPs, most of which act as expression or splicing quantitative trait loci (eQTLs/sQTLs) in genes previously associated with AD or with a possible functional role in the disease, such as CELF1, MADD, MYBPC3, NR1H3, NUP160, SPI1, and TOMM40. Interestingly, eight of these variants are located within long non-coding RNA (lncRNA) genes that have not been previously investigated regarding AD. Some of these polymorphisms can result in changes in these lncRNAs' secondary structures, leading to either loss or gain of microRNA (miRNA)-binding sites, deregulating downstream pathways. Our pioneering work not only replicated LOAD association with polymorphisms not yet associated in the Brazilian population but also identified six possible lncRNAs that may interfere in LOAD development. The results lead us to emphasize the importance of functional exploration of associations found in large-scale association studies in different populations to base personalized and inclusive medicine in the future.
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Affiliation(s)
- Gabriela Canalli Kretzschmar
- Laboratory of Human Molecular Genetics, Postgraduate Program in Genetics, Department of Genetics, Federal University of Paraná, Curitiba, Brazil
| | - Nina Moura Alencar
- Laboratory of Human Molecular Genetics, Postgraduate Program in Genetics, Department of Genetics, Federal University of Paraná, Curitiba, Brazil
| | - Saritha Suellen Lopes da Silva
- Laboratory of Polymorphism and Linkage, Postgraduate Program in Genetics, Department of Genetics, Federal University of Paraná, Curitiba, Brazil
| | - Carla Daniela Sulzbach
- Laboratory of Polymorphism and Linkage, Postgraduate Program in Genetics, Department of Genetics, Federal University of Paraná, Curitiba, Brazil
| | - Caroline Grisbach Meissner
- Laboratory of Human Molecular Genetics, Postgraduate Program in Genetics, Department of Genetics, Federal University of Paraná, Curitiba, Brazil
| | - Maria Luiza Petzl-Erler
- Laboratory of Human Molecular Genetics, Postgraduate Program in Genetics, Department of Genetics, Federal University of Paraná, Curitiba, Brazil
| | - Ricardo Lehtonen R. Souza
- Laboratory of Polymorphism and Linkage, Postgraduate Program in Genetics, Department of Genetics, Federal University of Paraná, Curitiba, Brazil
| | - Angelica Beate Winter Boldt
- Laboratory of Human Molecular Genetics, Postgraduate Program in Genetics, Department of Genetics, Federal University of Paraná, Curitiba, Brazil
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Josviak ND, Batistela MS, Souza RKM, Wegner NR, Bono GF, Sulzbach CD, Simão-Silva DP, Piovezan MR, Souza RLR, Furtado-Alle L. Plasma butyrylcholinesterase activity: a possible biomarker for differential diagnosis between Alzheimer's disease and dementia with Lewy bodies? Int J Neurosci 2017; 127:1082-1086. [PMID: 28504037 DOI: 10.1080/00207454.2017.1329203] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Butyrylcholinesterase (BChE) is an enzyme encoded by BCHE gene, responsible for secondary hydrolysis of the acetylcholine. K and -116A BCHE variants were associated with decrease in plasma BChE activity, and their influence has been investigated in diseases with a cholinergic deficit such as Alzheimer's disease (AD) and dementia with Lewy bodies (DLB). In order to check the influence of BCHE genetic variants on enzymatic activity, all patients and controls were genotyped for K and -116A variants. We found lower plasma BChE activity in DLB patients compared to elderly controls and to AD independent of the presence of K or -116A variants. Our results suggest that the reduction of total plasma BChE activity is probably associated with a feedback mechanism and provides a future perspective of using this enzyme as a possible plasmatic marker for differential diagnosis between AD and DLB.
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Affiliation(s)
- N D Josviak
- a Department of Genetics , Federal University of Parana , Curitiba , Brazil
| | - M S Batistela
- a Department of Genetics , Federal University of Parana , Curitiba , Brazil
| | - R K M Souza
- b Ambulatory of Memory and Behavior Disorders , Neurology Institute of Curitiba , Curitiba , Brazil
| | - N R Wegner
- a Department of Genetics , Federal University of Parana , Curitiba , Brazil
| | - G F Bono
- a Department of Genetics , Federal University of Parana , Curitiba , Brazil
| | - C D Sulzbach
- a Department of Genetics , Federal University of Parana , Curitiba , Brazil
| | - D P Simão-Silva
- a Department of Genetics , Federal University of Parana , Curitiba , Brazil
| | - M R Piovezan
- c Department of Neurology , Clinical Hospital of the Federal University of Paraná , Curitiba , Brazil
| | - R L R Souza
- a Department of Genetics , Federal University of Parana , Curitiba , Brazil
| | - L Furtado-Alle
- a Department of Genetics , Federal University of Parana , Curitiba , Brazil
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Batistela MS, Josviak ND, Sulzbach CD, de Souza RLR. An overview of circulating cell-free microRNAs as putative biomarkers in Alzheimer's and Parkinson's Diseases. Int J Neurosci 2016; 127:547-558. [PMID: 27381850 DOI: 10.1080/00207454.2016.1209754] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Circulating cell-free microRNAs (miRNAs) are stable in many biological fluids and their expression profiles can suffer changes under different physiological and pathological conditions. In the last few years, miRNAs have been proposed as putative noninvasive biomarkers in diagnosis, prognosis and response to treatment for several diseases, including neurodegenerative disorders as Alzheimer's disease (AD) and Parkinson's disease (PD). Cognitive and/or motor impairments are usually considered for establishing clinical diagnosis, and at this stage, the majority of the neurons may already be lost making difficult attempts of novel therapies. In this review, we intend to survey the circulating cell-free miRNAs found as dysregulated in cerebrospinal fluid, serum and plasma samples in AD and PD patients, and show how those miRNAs can be useful for early and differential diagnosis. Beyond that, we highlighted the miRNAs that are possibly related to common molecular mechanisms in the neurodegeneration process, as well those miRNAs related to specific disease pathways.
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