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Aim: Dietary miRNAs in foods were recently suggested to be absorbed into the human circulation and engage in human gene regulation. This started a debate on their possible impacts on human diseases which need further investigation. In this study, we aimed to identify the putative functions and possible implications of selected Xeno-miRs in human diseases by using bioinformatic tools. Methods: Seventy-five human absorbable Xeno-miR candidates were selected from literature and narrowed down the list to miRNAs that share sequence homologies with human miRNAs. Sixteen distinct Xeno-miRs of animal species (cow, pig, chicken) were identified to have homologs in human and they were subsequently analyzed with target prediction, functional and pathway analysis tools. Results and Conclusion: Thirteen human genes were common targets of the miRNA sets grouped by species and shown evidence of associations with various cancer categories, specifically in large intestine adenocarcinoma by Ingenuity Pathway Analysis. miRNA functional enrichment analyses also highlighted the putative involvements of the dietary miRNAs in cancer pathways. Our effort provides "in silico" evidence for implications of animal-derived dietary miRNAs in cancer-associated pathways, and this shed on light the necessities of future translational research design to investigate the roles of dietary Xeno-miRs in cancer pathophysiology and nutrition-based interventions towards cancer management.
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Dieta/efectos adversos , MicroARNs/genética , Neoplasias/genética , Animales , Bovinos , Pollos/genética , Biología Computacional , Simulación por Computador , Alimentos/efectos adversos , Regulación de la Expresión Génica , Humanos , MicroARNs/metabolismo , Neoplasias/etiología , ARN de Planta/genética , Homología de Secuencia , Porcinos/genéticaRESUMEN
Coronary artery disease (CAD) is still the preliminary cause of mortality and morbidity in the developed world. Identification of novel predictive and therapeutic biomarkers is crucial for accurate diagnosis, prognosis and treatment of the CAD. The aim of this study was to detect novel candidate miRNA biomarker that may be used in the management of CAD. We performed miRNA profiling in whole blood samples of angiographically confirmed Turkish men with CAD and non-CAD controls with insignificant coronary stenosis. Validation of microarray results was performed by qRT-PCR in a larger cohort of 62 samples. We subsequently assessed the diagnostic value of the miRNA and correlations of miRNA with clinical parameters. miRNA-target identification and network analyses were conducted by Ingenuity Pathway Analysis (IPA) software. Hsa-miR-584-5p was one of the top significantly dysregulated miRNA observed in miRNA microarray. Men-specific down-regulation (p = 0.040) of hsa-miR-584-5p was confirmed by qRT-PCR. ROC curve analysis highlighted the potential diagnostic value of hsa-miR-584-5p with a power area under the curve (AUC) of 0.714 and 0.643 in men and in total sample, respectively. The expression levels of hsa-miR-584-5p showed inverse correlation with stenosis and Gensini scores. IPA revealed CDH13 as the only CAD related predicted target for the miRNA with biological evidence of its involvement in CAD. This study suggests that hsa-miR-584-5p, known to be tumor suppressor miRNA, as a candidate biomarker for CAD and highlighted its putative role in the CAD pathogenesis. The validation of results in larger samples incorporating functional studies warrant further research.
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Enfermedad de la Arteria Coronaria/genética , MicroARNs/metabolismo , Biomarcadores/metabolismo , Estudios de Casos y Controles , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Humanos , Masculino , MicroARNs/genética , Persona de Mediana Edad , Sensibilidad y Especificidad , Programas Informáticos , TurquíaRESUMEN
BACKGROUND: High-density lipoprotein cholesterol (HDL-C) exerts many anti-atherogenic properties including its role in reverse cholesterol transport (RCT). Scavenger receptor class B member 1 (SCARB1) plays a key role in RCT by selective uptake of HDL cholesteryl esters. We aimed to explore the genetic contribution of SCARB1 to affecting lipid levels in African Blacks from Nigeria. METHODS: We resequenced 13 exons and exon-intron boundaries of SCARB1 in 95 individuals with extreme HDL-C levels using Sanger method. Then, we genotyped 147 selected variants (78 sequence variants, 69 HapMap tagSNPs, and 2 previously reported relevant variants) in the entire sample of 788 African Blacks using either the iPLEX Gold or TaqMan methods. A total of 137 successfully genotyped variants were further evaluated for association with major lipid traits. RESULTS: The initial gene-based analysis demonstrated evidence of association with HDL-C and apolipoprotein A-I (ApoA-I). The follow-up single-site analysis revealed nominal evidence of novel associations of nine common variants with HDL-C and/or ApoA-I (P < 0.05). The strongest association was between rs11057851 and HDL-C (P = 0.0043), which remained significant after controlling for multiple testing using false discovery rate. Rare variant association testing revealed a group of 23 rare variants (frequencies ≤ 1%) associated with HDL-C (P = 0.0478). Haplotype analysis identified four SCARB1 regions associated with HDL-C (global P < 0.05). CONCLUSIONS: To our knowledge, this is the first report of a comprehensive association study of SCARB1 variations with lipid traits in an African Black population. Our results showed the consistent association of SCARB1 variants with HDL-C across various association analyses, supporting the role of SCARB1 in lipoprotein-lipid regulatory mechanism.
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Estudios de Asociación Genética/métodos , Variación Genética , Lípidos/sangre , Receptores Depuradores de Clase B/genética , Adulto , Anciano , Apolipoproteína A-I/sangre , Población Negra/genética , HDL-Colesterol/sangre , Femenino , Frecuencia de los Genes , Genotipo , Haplotipos , Humanos , Modelos Lineales , Masculino , Persona de Mediana Edad , Nigeria , Fenotipo , Polimorfismo de Nucleótido Simple , Análisis de Secuencia de ADN , Adulto JovenRESUMEN
Lipoprotein lipase (LPL) plays a crucial role in lipid metabolism by hydrolyzing triglyceride (TG)-rich particles and affecting HDL cholesterol (HDL-C) levels. In this study, the entire LPL gene plus flanking regions were resequenced in individuals with extreme HDL-C/TG levels (n = 95), selected from a population-based sample of 623 US non-Hispanic White (NHW) individuals. A total of 176 sequencing variants were identified, including 28 novel variants. A subset of 64 variants [common tag single nucleotide polymorphisms (tagSNP) and selected rare variants] were genotyped in the total sample, followed by association analyses with major lipid traits. A gene-based association test including all genotyped variants revealed significant association with HDL-C (P = 0.024) and TG (P = 0.006). Our single-site analysis revealed seven independent signals (P < 0.05; r² < 0.40) with either HDL-C or TG. The most significant association was for the SNP rs295 exerting opposite effects on TG and HDL-C levels with P values of 7.5.10â»4 and 0.002, respectively. Our work highlights some common variants and haplotypes in LPL with significant associations with lipid traits; however, the analysis of rare variants using burden tests and SKAT-O method revealed negligible effects on lipid traits. Comprehensive resequencing of LPL in larger samples is warranted to further test the role of rare variants in affecting plasma lipid levels.
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HDL-Colesterol/sangre , Lipoproteína Lipasa/genética , Triglicéridos/sangre , Adulto , Anciano , Estudios de Casos y Controles , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/genética , Femenino , Frecuencia de los Genes , Estudios de Asociación Genética , Haplotipos , Humanos , Desequilibrio de Ligamiento , Masculino , Persona de Mediana Edad , Anotación de Secuencia Molecular , Polimorfismo de Nucleótido Simple , Análisis de Secuencia de ADNRESUMEN
TSPO protein is known to be involved in various cellular functions and dysregulations of TSPO expression has been found to be associated with pathologies of different human diseases, including cardiovascular disease, cancer, neuroinflammatory, neurodegenerative, neoplastic disorders. However, there are limited studies in the literature on the effects of sequence variations in the TSPO gene on the function of the protein and their relationship with human diseases. Evaluating the pathogenicity of genetic variants is crucial in terms of prioritizing the functional importance and clinical use. Therefore, various in-silico prediction tools have been developed that combine different algorithms to predict the effects of sequence variations on protein functions or gene regulation. In this study, the p-adic distance approach in modeling the genetic code, proposed and developed by Dragovich and Dragovich, was discussed in order to obtain an alternative to the existing in-silico prediction tools. Dragovichs' approach is expressed as follows: A 5-adic space of codons is constructed and 5-adic and 2-adic distances between codons are taken into account. As a result, two codons with the smallest value of 5-adic and 2-adic distances are obtained, encoded for the same amino acid and stop signal. This model describes well the degeneration of the genetic code. This study combined the data obtained from in-silico prediction tools and used a bioinformatics approach to determine the functional relevance of coding SNPs in the TSPO. Overall, we evaluate the potential utility of Dragovichs' approach by comparing it with other existing prediction tools for variant classification and prioritization.
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Receptores de GABA , Receptores de GABA/genética , Receptores de GABA/metabolismo , Humanos , Algoritmos , Codón/genética , Biología Computacional/métodos , Simulación por Computador , Código Genético/genética , Modelos GenéticosRESUMEN
Background and Aim: It is reported that miRNAs play an important role in hepatocellular carcinogenesis and may serve as non-invasive biomarkers for hepatocellular carcinoma (HCC). MiR-4510 and miR-146b-5p expression levels have been found to be associated with HCC. However, their associations with hepatitis B virus (HBV)-related HCC (HBV-HCC) are yet to be explored. We aimed to assess the predictive value of expression levels of serum miR-4510 and miR-146b-5p in patients with HBV-HCC and performed bioinformatics analyses based on the miRNA expression profile. Materials and Methods: This cross-sectional study used the serum of 16 patients with Chronic Hepatitis B (CHB), 15 hepatitis B virus-related cirrhosis (HBV-cirrhosis), 15 HBV-HCC, and 16 healthy subjects. The total RNA was isolated from serum, and the expression of miRNAs was measured by qRT-PCR, calculated using the 2-ΔΔCt methods. MIENTURNET was used to predict miRNA-target gene interactions. The Network Analyst was used to build protein-protein interactions. Results: There was a significant difference in miR-146b-5p between study groups (p=0.009). MiR-146b-5p expression was found to be significantly reduced in HBV-HCC compared to the HBV-cirrhosis group and healthy controls (p=0.005 and p=0.006, respectively). Conclusion: The serum miR-146b-5p levels might be a promising tool to be used as a non-invasive diagnostic biomarker for HCC. Our findings shed light on potential biomarkers for the diagnosis of HBV-HCC in terms of selected miRNAs. The target pathways of miR-146b-5p identified by our in-silico analysis to reveal the functional mechanism are "MAPK signaling pathways" and "Pathways in cancer."
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Growing evidence suggests that cigarette smoking alters the salivary microbiome composition and affects the risk of various complex diseases including cancer. However, the potential role of the smoking-associated microbiome in cancer development remains unexplained. Here, the putative roles of smoking-related microbiome alterations in carcinogenesis were investigated by in silico analysis and suggested evidence can be further explored by experimental methodologies. The Disbiome database was used to extract smoking-associated microbial taxa in saliva and taxon set enrichment analysis (TSEA) was conducted to identify the gene sets associated with extracted microbial taxa. We further analyzed the expression profiles of identified genes by using RNA-sequencing data from TCGA and GTEx projects. Associations of the genes with smoking-related phenotypes in cancer datasets were analyzed to prioritize genes for their interplay between smoking-related microbiome and carcinogenesis. Thirty-eight microbial taxa associated with smoking were included in the TSEA and this revealed sixteen genes that were significantly associated with smoking-associated microbial taxa. All genes were found to be differentially expressed in at least one cancer dataset, yet the ELF3 and CTSH were the most common differentially expressed genes giving significant results for several cancer types. Moreover, C2CD3, CTSH, DSC3, ELF3, RHOT2, and WSB2 showed statistically significant associations with smoking-related phenotypes in cancer datasets. This study provides in silico evidence for the potential roles of the salivary microbiome on carcinogenesis. The results shed light on the importance of smoking cessation strategies for cancer management and interventions to stratify smokers for their risk of smoking-induced carcinogenesis.
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Microbiota , Humanos , Microbiota/genética , Saliva , Carcinogénesis , ARN Ribosómico 16S , Fumar/efectos adversos , Fumar/genética , Proteínas Asociadas a MicrotúbulosRESUMEN
BACKGROUND: Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths and mining the molecular factors underlying CRC pathogenesis is imperative for alleviating the disease burden. OBJECTIVE: To highlight key molecular pathways, prioritize hub genes and their regulators related to CRC. METHODS: Data sets of TCGA-COAD and GTEx were used to identify differentially expressed genes (DEGs) and their functional enrichments in pathways and biological processes were analyzed using bioinformatics tools. Protein-protein interaction network was constructed and hub genes were identified using Cytoscape. Ingenuity Pathway Analysis was used to analyze the relations of the hub genes with diseases and canonical pathways. Key regulators targeting the hub genes such as TFs, miRNAs and their interactions were identified using in silico tools. RESULTS: AURKA, CDK1, MYC, CDH1, CCNB1, CDC20, UBE2C, PLK1, KIF11, and CCNA2 were prioritized as hub genes based on their topological properties. Enrichment analyses emphasized the roles of DEGs and hub genes in the cell cycle process. Interactions of the hub genes with TFs and miRNAs suggested TP53, EZH2 and KLF4 as being promising candidate biomarkers for CRC. CONCLUSIONS: Our results provide in silico evidence for candidate biomolecules that may have strong biomarker potential for CRC-related translational strategies.
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Biomarcadores de Tumor/genética , Neoplasias Colorrectales/genética , MicroARNs/genética , Biomarcadores de Tumor/metabolismo , Ciclo Celular/genética , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Biología Computacional/métodos , Bases de Datos Genéticas , Perfilación de la Expresión Génica/métodos , Humanos , Factor 4 Similar a Kruppel , Mapas de Interacción de Proteínas , Transducción de SeñalRESUMEN
Pathogenic variants in the coding regions of the BRCA1/2 lead dysfunctional or nonfunctional BRCA proteins however the contribution of non-coding BRCA1/2 variants to BRCA-related disease risk has not been fully elucidated. Thus, we characterized the functional impact of both coding and non-coding BRCA1/2 variants identified in individuals with personal and/or family history of BRCA-related cancers. The data were produced by resequencing the exons and exon-intron junctions of the BRCA1/2 in 125 individuals and were comprehensively analyzed by using bioinformatics tools and databases. A total of 96 variants (59 coding and 37 non-coding) including 7 novel variants were identified and analyzed for their functional importance. We identified 11 missense variants that potentially affect protein function; 22 variants were likely to alter different types of posttranslational modifications. Also, multiple non-coding BRCA1/2 variants were found to reside in the critical regulatory regions that have the potential to act as eQTLs and affect alternative splicing. The results of our study shed light on the possible contributions of not only coding variants but also non-coding BRCA1/2 variants in BRCRA-related cancers. Further investigation is required to fully understand their potential associations with phenotypes which may ultimately lead their utilization on cancer management as a biomarker.
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Proteína BRCA1/genética , Proteína BRCA2/genética , Simulación por Computador , Mutación Missense , Neoplasias/genética , Procesamiento Proteico-Postraduccional , HumanosRESUMEN
Genome-wide association studies (GWAS) of coronary artery disease (CAD) have revealed multiple genetic risk loci. We assessed the association of 47 genome-wide significant single-nucleotide polymorphisms (SNPs) at 43 CAD loci with coronary stenosis in a Pakistani sample comprising 663 clinically ascertained and angiographically confirmed cases. Genotypes were determined using the iPLEX Gold technology. All statistical analyses were performed using R software. Linkage disequilibrium (LD) between significant SNPs was determined using SNAP web portal, and functional annotation of SNPs was performed using the RegulomeDB and Genotype-Tissue Expression (GTEx) databases. Genotyping comparison was made between cases with severe stenosis (≥70%) and mild/minimal stenosis (<30%). Five SNPs demonstrated significant associations: three with additive genetic models PLG/rs4252120 (p = 0.0078), KIAA1462/rs2505083 (p = 0.005), and SLC22A3/rs2048327 (p = 0.045) and two with recessive models SORT1/rs602633 (p = 0.005) and UBE2Z/rs46522 (p = 0.03). PLG/rs4252120 was in LD with two functional PLG variants (rs4252126 and rs4252135), each with a RegulomeDB score of 1f. Likewise, KIAA1462/rs2505083 was in LD with a functional SNP, KIAA1462/rs3739998, having a RegulomeDB score of 2b. In the GTEx database, KIAA1462/rs2505083, SLC22A3/rs2048327, SORT1/rs602633, and UBE2Z/rs46522 SNPs were found to be expression quantitative trait loci (eQTLs) in CAD-associated tissues. In conclusion, five genome-wide significant SNPs previously reported in European GWAS were replicated in the Pakistani sample. Further association studies on larger non-European populations are needed to understand the worldwide genetic architecture of CAD.
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Enfermedad de la Arteria Coronaria/genética , Estenosis Coronaria/genética , Polimorfismo de Nucleótido Simple , Adulto , Anciano , Moléculas de Adhesión Celular/genética , Femenino , Estudio de Asociación del Genoma Completo , Humanos , Masculino , Persona de Mediana Edad , Proteínas de Transporte de Catión Orgánico/genética , Pakistán , Sitios de Carácter Cuantitativo , Enzimas Ubiquitina-Conjugadoras/genética , Población Blanca/genéticaRESUMEN
Common variants in the hepatic lipase (LIPC) gene have been shown to be associated with plasma lipid levels; however, the distribution and functional features of rare and regulatory LIPC variants contributing to the extreme lipid phenotypes are not well known. This study was aimed to catalogue LIPC variants by resequencing the entire LIPC gene in 95 non-Hispanic Whites (NHWs) and 95 African blacks (ABs) with extreme HDL-C levels followed by in silico functional analyses. A total of 412 variants, including 43 novel variants were identified; 56 were unique to NHWs and 234 were unique to ABs. Seventy-eight variants in NHWs and 89 variants in ABs were present either in high HDL-C group or low HDL-C group. Two non-synonymous variants (p.S289F, p.T405M), found in NHWs with high HDL-C group were predicted to have damaging effect on LIPC protein by SIFT, MT2 and PP2. We also found several non-coding variants that possibly reside in the circRNA and lncRNA binding sites and may have regulatory potential, as identified in rSNPbase and RegulomeDB databases. Our results shed light on the regulatory nature of rare and non-coding LIPC variants as well as suggest their important contributions in affecting the extreme HDL-C phenotypes.
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HDL-Colesterol/sangre , LDL-Colesterol/sangre , Lipasa/genética , Negro o Afroamericano , Alelos , Sitios de Unión/genética , Colesterol/sangre , Colesterol/genética , Proteínas de Transferencia de Ésteres de Colesterol/sangre , Proteínas de Transferencia de Ésteres de Colesterol/genética , HDL-Colesterol/genética , LDL-Colesterol/genética , Femenino , Genotipo , Humanos , Intrones/genética , Lipasa/ultraestructura , Metabolismo de los Lípidos/genética , Lípidos/sangre , Lípidos/genética , Masculino , Polimorfismo de Nucleótido Simple , Unión Proteica/genética , Conformación Proteica , ARN Circular/sangre , ARN Circular/genética , ARN Largo no Codificante/genética , Triglicéridos/sangre , Triglicéridos/genética , Población BlancaRESUMEN
The apolipoprotein E-C1-C4-C2 gene cluster at 19q13.32 encodes four amphipathic apolipoproteins. The influence of APOE common polymorphisms on plasma lipid/lipoprotein profile, especially on LDL-related traits, is well recognized; however, little is known about the role of other genes/variants in this gene cluster. In this study, we evaluated the role of common and uncommon/rare genetic variation in this gene region on inter-individual variation in plasma lipoprotein levels in non-Hispanic Whites (NHWs) and African blacks (ABs). In the variant discovery step, the APOE, APOC1, APOC4, APOC2 genes were sequenced along with their flanking and hepatic control regions (HCR1 and HCR2) in 190 subjects with extreme HDL-C/TG levels. The next step involved the genotyping of 623 NHWs and 788 ABs for the identified uncommon/rare variants and common tagSNPs along with additional relevant SNPs selected from public resources, followed by association analyses with lipid traits. A total of 230 sequence variants, including 15 indels were identified, of which 65 were novel. A total of 70 QC-passed variants in NHWs and 108 QC-passed variants in ABs were included in the final association analyses. Single-site association analysis of SNPs with MAF>1% revealed 20 variants in NHWs and 24 variants in ABs showing evidence of association with at least one lipid trait, including several variants exhibiting independent associations from the established APOE polymorphism even after multiple-testing correction. Overall, our study has confirmed known associations and also identified novel associations in this genomic region with various lipid traits. Our data also support the contribution of both common and uncommon/rare variation in this gene region in affecting plasma lipid profile in the general population.
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Apolipoproteína C-II/genética , Apolipoproteína C-I/genética , Apolipoproteínas C/genética , Apolipoproteínas E/genética , Etnicidad/genética , Lipoproteínas/sangre , Adulto , Población Negra/genética , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Dislipidemias/sangre , Dislipidemias/genética , Femenino , Estudios de Asociación Genética , Genotipo , Haplotipos , Humanos , Masculino , Persona de Mediana Edad , Familia de Multigenes , Polimorfismo de Nucleótido Simple , Triglicéridos/sangre , Población Blanca/genéticaRESUMEN
BACKGROUND: Cholesteryl ester transfer protein (CETP) plays a crucial role in lipid metabolism. Associations of common CETP variants with variation in plasma lipid levels, and/or CETP mass/activity have been extensively studied and well-documented; however, the effects of uncommon/rare CETP variants on plasma lipid profile remain undefined. Hence, resequencing of the gene in extreme phenotypes and follow-up rare-variant association analyses are essential to fill this gap. OBJECTIVE: To identify common and uncommon/rare variants in the CETP gene by resequencing the entire gene and test the effects of both common and uncommon/rare CETP variants on plasma lipid traits in two genetically distinct populations. METHODS AND RESULTS: The entire CETP gene plus flanking regions were resequenced in 190 individuals comprising 95 non-Hispanic whites (NHWs) and 95 African blacks with extreme HDL-C levels. A total of 279 sequence variants were identified, of which 25 were novel. Selected variants were genotyped in the entire samples of 623 NHWs and 788 African blacks and 184 QC-passed variants were tested in relation to plasma lipid traits by using gene-based, single-site, haplotype and rare variant association analyses (SKAT-O). Two novel and independent associations of rs1968905 and rs289740 with HDL-C were identified in African blacks. Using SKAT-O analysis, we also identified rare variants with minor allele frequency <0.01 to be associated with HDL-C in both NHWs (P=0.024) and African blacks (P=0.009). CONCLUSIONS: Our results point out that in addition to the common CETP variants, rare genetic variants in the CETP gene also contribute to the phenotypic variation of HDL-C in the general population.
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Población Negra/genética , Proteínas de Transferencia de Ésteres de Colesterol/genética , HDL-Colesterol/sangre , Población Blanca/genética , Adulto , Anciano , Femenino , Genotipo , Haplotipos , Humanos , Desequilibrio de Ligamiento , Masculino , Persona de Mediana Edad , Análisis de Secuencia de ADNRESUMEN
Genome-wide association studies have identified several loci associated with plasma lipid levels but those common variants together account only for a small proportion of the genetic variance of lipid traits. It has been hypothesized that the remaining heritability may partly be explained by rare variants with strong effect sizes. Here, we have comprehensively investigated the associations of both common and uncommon/rare variants in the lipoprotein lipase (LPL) gene in relation to plasma lipoprotein-lipid levels in African Blacks (ABs). For variant discovery purposes, the entire LPL gene and flanking regions were resequenced in 95 ABs with extreme high-density lipoprotein cholesterol (HDL-C) levels. A total of 308 variants were identified, of which 64 were novel. Selected common tagSNPs and uncommon/rare variants were genotyped in the entire sample (n=788), and 126 QC-passed variants were evaluated for their associations with lipoprotein-lipid levels by using single-site, haplotype and rare variant (SKAT-O) association analyses. We found eight not highly correlated (r(2)<0.40) signals (rs1801177:G>A, rs8176337:G>C, rs74304285:G>A, rs252:delA, rs316:C>A, rs329:A>G, rs12679834:T>C, and rs4921684:C>T) nominally (P<0.05) associated with lipid traits (HDL-C, LDL-C, ApoA1 or ApoB levels) in our sample. The most significant SNP, rs252:delA, represented a novel association observed with LDL-C (P=0.002) and ApoB (P=0.012). For TG and LDL-C, the haplotype analysis was more informative than the single-site analysis. The SKAT-O analysis revealed that the bin (group) containing 22 rare variants with MAF≤0.01 exhibited nominal association with TG (P=0.039) and LDL-C (P=0.027). Our study indicates that both common and uncommon/rare LPL variants/haplotypes may affect plasma lipoprotein-lipid levels in general African population.
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Apolipoproteína A-I/genética , Apolipoproteínas B/genética , Genoma Humano , Lipoproteína Lipasa/genética , Polimorfismo de Nucleótido Simple , Adulto , Alelos , Apolipoproteína A-I/sangre , Apolipoproteínas B/sangre , Población Negra , HDL-Colesterol/sangre , HDL-Colesterol/genética , LDL-Colesterol/sangre , LDL-Colesterol/genética , Femenino , Expresión Génica , Frecuencia de los Genes , Estudio de Asociación del Genoma Completo , Haplotipos , Humanos , Metabolismo de los Lípidos/genética , Lipoproteína Lipasa/sangre , Masculino , Persona de Mediana Edad , Nigeria , Fenotipo , Análisis de Secuencia de ADN , Triglicéridos/sangre , Triglicéridos/genéticaRESUMEN
BACKGROUND: Scavenger receptor class B type 1 (SCARB1) plays an important role in high-density lipoprotein cholesterol (HDL-C) metabolism in selective cholesteryl ester uptake and in free cholesterol cellular efflux. METHODS AND RESULTS: This study aims to identify common (minor allele frequency ≥5%) and low-frequency/rare (minor allele frequency <5%) variants, using resequencing all 13 exons and exon-intron boundaries of SCARB1 in 95 individuals with extreme HDL-C levels selected from a population-based sample of 623 US non-Hispanic whites. The sequencing step identified 44 variants, of which 11 were novel with minor allele frequency <1%. Seventy-six variants (40 sequence variants, 32 common HapMap tag single nucleotide polymorphisms, and 4 relevant variants) were selected for genotyping in the total sample of 623 subjects followed by association analyses with lipid traits. Seven variants were nominally associated with apolipoprotein B (apoB; n=4) or HDL-C (n=3; P<0.05). Three variants associated with apoB remained significant after controlling false discovery rate. The most significant association was observed between rs4765615 and apoB (P=0.0059), while rs11057844 showed the strongest association with HDL-C (P=0.0035). A set of 17 rare variants (minor allele frequency ≤1%) showed significant association with apoB (P=0.0284). Haplotype analysis revealed 4 regions significantly associated with either apoB or HDL-C. CONCLUSIONS: Our findings provide new information about the genetic role of SCARB1 in affecting plasma apoB levels in addition to its established role in HDL-C metabolism.
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HDL-Colesterol/sangre , Variación Genética , Receptores Depuradores de Clase B/genética , Adulto , Anciano , Alelos , Apolipoproteínas B/genética , Frecuencia de los Genes , Estudios de Asociación Genética , Genotipo , Haplotipos , Humanos , Desequilibrio de Ligamiento , Persona de Mediana Edad , Fenotipo , Polimorfismo de Nucleótido Simple , Análisis de Secuencia de ADNRESUMEN
Although common APOE genetic variation has a major influence on plasma LDL-cholesterol, its role in affecting HDL-cholesterol and triglycerides is not well established. Recent genome-wide association studies suggest that APOE also affects plasma variation in HDL-cholesterol and triglycerides. It is thus important to resequence the APOE gene to identify both common and uncommon variants that affect plasma lipid profile. Here, we have sequenced the APOE gene in 190 subjects with extreme HDL-cholesterol levels selected from two well-defined epidemiological samples of U.S. non-Hispanic Whites (NHWs) and African Blacks followed by genotyping of identified variants in the entire datasets (623 NHWs, 788 African Blacks) and association analyses with major lipid traits. We identified a total of 40 sequence variants, of which 10 are novel. A total of 32 variants, including common tagSNPs (≥5% frequency) and all uncommon variants (<5% frequency) were successfully genotyped and considered for genotype-phenotype associations. Other than the established associations of APOE*2 and APOE*4 with LDL-cholesterol, we have identified additional independent associations with LDL-cholesterol. We have also identified multiple associations of uncommon and common APOE variants with HDL-cholesterol and triglycerides. Our comprehensive sequencing and genotype-phenotype analyses indicate that APOE genetic variation impacts HDL-cholesterol and triglycerides in addition to affecting LDL-cholesterol.