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Aim: Methylation of LDLR, PCSK9 and LDLRAP1 CpG sites was assessed in patients with familial hypercholesterolemia (FH). Methods: DNA methylation of was analyzed by pyrosequencing in 131 FH patients and 23 normolipidemic (NL) subjects. Results: LDLR, PCSK9 and LDLRP1 methylation was similar between FH patients positive (MD) and negative (non-MD) for pathogenic variants in FH-related genes. LDLR and PCSK9 methylation was higher in MD and non-MD groups than NL subjects (p < 0.05). LDLR, PCSK9 and LDLRAP1 methylation profiles were associated with clinical manifestations and cardiovascular events in FH patients (p < 0.05). Conclusion: Differential methylation of LDLR, PCSK9 and LDLRAP1 is associated with hypercholesterolemia and cardiovascular events. This methylation profile maybe useful as a biomarker and contribute to the management of FH.
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OBJECTIVES: This study explored the association of deleterious variants in pharmacodynamics (PD) genes with statin response and adverse effects in patients with familial hypercholesterolemia (FH) and analyzed their potential effects on protein structure and stability. METHODS: Clinical and laboratory data were obtained from 144 adult FH patients treated with statins. A panel of 32 PD genes was analyzed by exon-targeted gene sequencing. Deleterious variants were identified using prediction algorithms and their structural effects were analyzed by molecular modeling studies. RESULTS: A total of 102 variants were predicted as deleterious (83 missense, 8 stop-gain, 4 frameshift, 1 indel, 6 splicing). The variants ABCA1 rs769705621 (indel), LPA rs41267807 (p.Tyr2023Cys) and KIF6 rs20455 (p.Trp719Arg) were associated with reduced low-density lipoprotein cholesterol (LDLc) response to statins, and the LPL rs1801177 (p.Asp36Asn) with increased LDLc response (P < 0.05). LPA rs3124784 (p.Arg2016Cys) was predicted to increase statin response (P = 0.022), and ABCA1 rs769705621 to increase the risk of statin-related adverse events (SRAE) (P = 0.027). LPA p.Arg2016Cys and LPL p.Asn36Asp maintained interactions with solvent, LPA p.Tyr2023Cys reduced intramolecular interaction with Gln1987, and KIF6 p.Trp719Arg did not affect intramolecular interactions. DDMut analysis showed that LPA p.Arg2016Cys and p.Tyr2023Cys and LPL p.Asp36Asn caused energetically favorable changes, and KIF6 p.Trp719Arg resulted in unfavorable energetic changes, affecting protein stability. CONCLUSION: Deleterious variants in ABCA1, LPA, LPL and KIF6 are associated with variability in LDLc response to statins, and ABCA1 rs769705621 is associated with SRAE risk in FH patients. Molecular modeling studies suggest that LPA p.Tyr2023Cys and KIF6 p.Trp719Arg disturb protein conformational structure and stability.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Hydroxymethylglutaryl-CoA Reductase Inhibitors , ATP Binding Cassette Transporter 1 , Hyperlipoproteinemia Type II , Lipoprotein LipaseABSTRACT
AIM: Methylation of LDLR, PCSK9 and LDLRAP1 CpG sites was assessed in patients with familial hypercholesterolemia (FH). METHODS: DNA methylation of was analyzed by pyrosequencing in 131 FH patients and 23 normolipidemic (NL) subjects. RESULTS: LDLR, PCSK9 and LDLRP1 methylation was similar between FH patients positive (MD) and negative (non-MD) for pathogenic variants in FH-related genes. LDLR and PCSK9 methylation was higher in MD and non-MD groups than NL subjects (p < 0.05). LDLR, PCSK9 and LDLRAP1 methylation profiles were associated with clinical manifestations and cardiovascular events in FH patients (p < 0.05). CONCLUSION: Differential methylation of LDLR, PCSK9 and LDLRAP1 is associated with hypercholesterolemia and cardiovascular events. This methylation profile maybe useful as a biomarker and contribute to the management of FH.
ABSTRACT
OBJECTIVES: This study explored the association of deleterious variants in pharmacodynamics (PD) genes with statin response and adverse effects in patients with familial hypercholesterolemia (FH) and analyzed their potential effects on protein structure and stability. METHODS: Clinical and laboratory data were obtained from 144 adult FH patients treated with statins. A panel of 32 PD genes was analyzed by exon-targeted gene sequencing. Deleterious variants were identified using prediction algorithms and their structural effects were analyzed by molecular modeling studies. RESULTS: A total of 102 variants were predicted as deleterious (83 missense, 8 stop-gain, 4 frameshift, 1 indel, 6 splicing). The variants ABCA1 rs769705621 (indel), LPA rs41267807 (p.Tyr2023Cys) and KIF6 rs20455 (p.Trp719Arg) were associated with reduced low-density lipoprotein cholesterol (LDLc) response to statins, and the LPL rs1801177 (p.Asp36Asn) with increased LDLc response (Pâ <â 0.05). LPA rs3124784 (p.Arg2016Cys) was predicted to increase statin response (Pâ =â 0.022), and ABCA1 rs769705621 to increase the risk of statin-related adverse events (SRAE) (Pâ =â 0.027). LPA p.Arg2016Cys and LPL p.Asn36Asp maintained interactions with solvent, LPA p.Tyr2023Cys reduced intramolecular interaction with Gln1987, and KIF6 p.Trp719Arg did not affect intramolecular interactions. DDMut analysis showed that LPA p.Arg2016Cys and p.Tyr2023Cys and LPL p.Asp36Asn caused energetically favorable changes, and KIF6 p.Trp719Arg resulted in unfavorable energetic changes, affecting protein stability. CONCLUSION: Deleterious variants in ABCA1, LPA, LPL and KIF6 are associated with variability in LDLc response to statins, and ABCA1 rs769705621 is associated with SRAE risk in FH patients. Molecular modeling studies suggest that LPA p.Tyr2023Cys and KIF6 p.Trp719Arg disturb protein conformational structure and stability.
Subject(s)
ATP Binding Cassette Transporter 1 , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Hyperlipoproteinemia Type II , Kinesins , Lipoprotein Lipase , Humans , Kinesins/genetics , Male , Female , Middle Aged , Hydroxymethylglutaryl-CoA Reductase Inhibitors/adverse effects , Hyperlipoproteinemia Type II/genetics , Hyperlipoproteinemia Type II/drug therapy , ATP Binding Cassette Transporter 1/genetics , Lipoprotein Lipase/genetics , Adult , Protein Stability , Cholesterol, LDL/blood , Polymorphism, Single NucleotideABSTRACT
Familial Hypercholesterolemia (FH) is a genetic disorder associated with premature atherosclerosis and increased risk of cardiovascular diseases. LDLR deleterious mutations are associated with FH, however the role of some missense variants in FH pathogenicity remains to be elucidated. This study explored the predictive impact of LDLR missense variants on protein structure and investigated their functional effects on LDLR expression in HepG2 cells transfected with CRISPR/Cas9 constructs. FH (n = 287) and non-FH patients (n = 45) were selected, and lipid profile was obtained from medical records. LDLR variants were identified using an exon-targeted gene sequencing strategy, considering its cost-effective to increase accuracy in the identification step of the most likely FH-related variants in a less laborious process. LDLR variants were selected based on conflicting pathogenicity results found in Clinvar, in silico prediction tools, affected LDLR domains, and less common variants considering minor allele frequency < 0.05. Molecular modeling studies were used to predict the effects of LDLR missense variants on protein structure. Recombinant LDLR variants were constructed using CRISPR/Cas9 system and were used to transfect HepG2 cells. Functional assays in transfected cells were performed to assess LDLR expression using flow cytometry and western blotting, and LDLR activity using flow cytometry and confocal microscopy. The variants rs121908039 (c.551G>A, p.C184Y), rs879254797 (c.1118G>A, p.G373D), rs28941776 (c.1646G>A, p.G549D), rs750518671 (c.2389G>C, p.V797L), rs5928 (c.2441G>A, p.R814Q) and rs137853964 (c.2479G>A, p.V827I) were selected for molecular docking analysis. The p.C184Y exhibited a favorable energy change for protein stability due to its interaction with EGF-A/EGF-B regions; p.G373D and p.G549D displayed intermediate energy changes; and p.R814Q and p.V827I showed smaller energy changes. The results of functional assays showed that p.G373D, p.V797L and p.R814Q reduced LDLR expression and activity (p < 0.05). Microscopic analysis of the p.V797L and p.G373D variants revealed altered lipid localization and accumulation in transfected HepG2 cells. Carriers of p.G549D, p.V797L and p.R814Q had higher LDL cholesterol levels than non-FH group, and (p < 0.05). p.G373D and p.G549D were associated with clinical manifestations of FH. In conclusion, the p.C184Y, p.G373D, p.G549D and p.R814Q variants alter protein stability and intramolecular interactions, while p.V797L has a minimal impact on protein stability, and p.V827I has no significant intramolecular interactions. p.G373D, p.V767L and p.R814Q are associated with impaired LDLR expression and activity.
Subject(s)
Hyperlipoproteinemia Type II , Blotting, WesternABSTRACT
Familial hypercholesterolemia (FH) is a disorder of lipid metabolism that causes elevated low-density lipoprotein cholesterol (LDL-c) and increased premature atherosclerosis risk. Statins inhibit endogenous cholesterol biosynthesis, which reduces LDL-c plasma levels and prevent from cardiovascular events. This study aimed to explore the effects of statin treatment on serum lipidomic profile and to identify biomarkers of response in subjects with FH. Seventeen adult FH patients underwent a 6-week washout followed by 4-week treatment with atorvastatin (80 mg/day) or rosuvastatin (40 mg/day). LDL-c response was considered good (4070 % reduction, n = 9) or poor (333 % reduction, n = 8). Serum lipidomic profile was analyzed by ultra-high-performance liquid chromatography combined with electrospray ionization tandem time-of-flight mass spectrometry, and data were analyzed using MetaboAnalyst v5.0. Lipidomic analysis identified 353 lipids grouped into 16 classes. Statin treatment reduced drastically 8 of 13 lipid classes, generating a characteristic lipidomic profile with a significant contribution of phosphatidylinositols (PI) 16:0/18:2, 18:0/18:1 and 18:0/18:2; and triacylglycerols (TAG) 18:2x2/18:3, 18:1/18:2/18:3, 16:1/18:2x2, 16:1/18:2/18:3 and 16:1/18:2/Arachidonic acid (p-adjusted <0.05). Biomarker analysis implemented in MetaboAnalyst subsequently identified PI 16:1/18:0, 16:0/18:2 and 18:0/18:2 as predictors of statin response with and receiver operating characteristic (ROC) areas under the curve of 0.98, 0.94 and 0.91, respectively. In conclusion, statins extensively modulate the overall serum lipid composition of FH individuals and these findings suggest that phosphatidyl-inositol molecules are potential predictive biomarkers of statin response.
Subject(s)
Biomarkers , Hyperlipoproteinemia Type II , Phosphatidylinositols , Hydroxymethylglutaryl-CoA Reductase Inhibitors , LipidomicsABSTRACT
BACKGROUND Familial hypercholesterolemia (FH) is caused by pathogenic variants in low-density lipoprotein (LDL) receptor (LDLR) or its associated genes, including apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and LDLR adaptor protein 1 (LDLRAP1). However, approximately 40% of the FH patients clinically diagnosed (based on FH phenotypes) may not carry a causal variant in a FH-related gene. Variants located at 3' untranslated region (UTR) of FH-related genes could elucidate mechanisms involved in FH pathogenesis. This study used a computational approach to assess the effects of 3'UTR variants in FH-related genes on miRNAs molecular interactions and to explore the association of these variants with molecular diagnosis of FH. METHODS AND RESULTS Exons and regulatory regions of FH-related genes were sequenced in 83 FH patients using an exon-target gene sequencing strategy. In silico prediction tools were used to study the effects of 3´UTR variants on interactions between miRNAs and target mRNAs. Pathogenic variants in FH-related genes (molecular diagnosis) were detected in 44.6% FH patients. Among 59 3'UTR variants identified, LDLR rs5742911 and PCSK9 rs17111557 were associated with molecular diagnosis of FH, whereas LDLR rs7258146 and rs7254521 and LDLRAP1 rs397860393 had an opposite effect (p < 0.05). 3´UTR variants in LDLR (rs5742911, rs7258146, rs7254521) and PCSK9 (rs17111557) disrupt interactions with several miRNAs, and more stable bindings were found with LDLR (miR-4435, miR-509-3 and miR-502) and PCSK9 (miR-4796). CONCLUSION LDLR and PCSK9 3´UTR variants disturb miRNA:mRNA interactions that could affect gene expression and are potentially associated with molecular diagnosis of FH.
Subject(s)
MicroRNAs , Hyperlipoproteinemia Type II , Proprotein Convertase 9ABSTRACT
INTRODUCTION AND OBJECTIVES: Apolipoprotein B plays a crucial role in regulating plasma cholesterol by mediating the interaction of low-density lipoprotein (LDL) with LDL receptors in the liver. Inherited mutations in this gene may increase the risk of developing premature atherosclerotic cardiovascular disease, especially in individuals with familial hypercholesterolemia type 2 (FH2). The aim of this study is to identify APOB variants that may indicate pathogenicity in a sample of the Brazilian population using a data bank exome sequencing study by NGS in a Brazilian population phenotypically diagnosed by clinical and laboratory profile. This finding is going to improve genetic hypercholesteremia diagnosis. Casuistic, Material and METHODS: High quality DNA samples (n=300) were sequenced using an exon- targeted gene sequencing (ETGS) strategy to identify variants in FH-related genes. Pathogenicity classification was based on criteria established by the American College of Medical Genetics and Genomics (ACMG), also using information from ClinVar and pathogenicity scores from previous association studies. RESULTS and CONCLUSIONS: A total of 121 variants were identified in APOB, of which four are novel variants missense (p.Thr626Asn, p.Ile2750Thr, p.Gln2078Lys and p.Met4184Arg). After curating pathogenicity scores, variants were classified according to the ACMG criteria. Among them four as pathogenic or likely pathogenic (p.Pro2739Leu, p.His1923Arg, p.Pro994Leu and p.Pro877Leu), and 21 variants had uncertain significance. Additionally, 92 previously known variants with uncertain significance were classified as benign or likely benign. The results were submitted to Clinvar for actualization of pathogenicity and to improve the molecular diagnosis associating APOB variants with the clinical phenotype of hypercholesterolemia. Financing: FAPESP, CNPQ, CAPES.
Subject(s)
CholesterolABSTRACT
Familial hypercholesterolemia (FH) is a monogenic disease characterized by high plasma low-density lipoprotein cholesterol (LDL-c) levels and increased risk of premature atherosclerotic cardiovascular disease. Mutations in FH-related genes account for 40% of FH cases worldwide. In this study, we aimed to assess the pathogenic variants in FH-related genes in the Brazilian FH cohort FHBGEP using exon-targeted gene sequencing (ETGS) strategy. FH patients (n = 210) were enrolled at five clinical sites and peripheral blood samples were obtained for laboratory testing and genomic DNA extraction. ETGS was performed using MiSeq platform (Illumina). To identify deleterious variants in LDLR, APOB, PCSK9, and LDLRAP1, the long-reads were subjected to Burrows-Wheeler Aligner (BWA) for alignment and mapping, followed by variant calling using Genome Analysis Toolkit (GATK) and ANNOVAR for variant annotation. The variants were further filtered using in-house custom scripts and classified according to the American College Medical Genetics and Genomics (ACMG) guidelines. A total of 174 variants were identified including 85 missense, 3 stop-gain, 9 splice-site, 6 InDel, and 71 in regulatory regions (3'UTR and 5'UTR). Fifty-two patients (24.7%) had 30 known pathogenic or likely pathogenic variants in FH-related genes according to the American College Medical and Genetics and Genomics guidelines. Fifty-three known variants were classified as benign, or likely benign and 87 known variants have shown uncertain significance. Four novel variants were discovered and classified as such due to their absence in existing databases. In conclusion, ETGS and in silico prediction studies are useful tools for screening deleterious variants and identification of novel variants in FH-related genes, they also contribute to the molecular diagnosis in the FHBGEP cohort.
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Abstract Background Cardiac arrest (CA) is a common condition associated with high mortality. The Brazilian advanced life support training TECA A (Treinamento em Emergências Cardiovasculares Avançado — Advanced Cardiovascular Emergency Training) was created to train healthcare professionals in the management of CA. However, there are no studies evaluating the effectiveness of TECA A. Objective To assess the impact of TECA A on the management of CA using a simulated CA situation. Methods Fifty-six students underwent a simulated case of CA in a manikin. The students' performance in the management of CA was assessed for the time to first chest compression and defibrillation and for a global assessment score using a structured tool. These items were assessed and compared before and after the TECA A. Exclusion criteria were previous participation in CA trainings and absence from class. Categorical variables were compared using the McNemar test and quantitative variables using the Wilcoxon test. All tests were two-tailed, and statistical significance was set at p < 0.05. Results Compared with before TECA A, median global assessment scores were higher after TECA A (pre-training: 4.0 points [2.0-5.0] vs. 10 points [9.0-10.0]; p<0.001), the time to start chest compressions was shorter (pre-training: 25 seconds [15-34] vs. 19 seconds [16.2-23.0]; p=0.002) and so was the time to defibrillation (pre-training: 82.5 seconds [65.0-108.0] vs. 48 seconds [39.0-53.0]; p<0.001). Conclusions The TECA A promoted a higher adherence to cardiopulmonary resuscitation (CPR) guidelines and a reduction in the time elapsed from CA to first chest compression and defibrillation.
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ABSTRACT: Familial hypercholesterolemia (FH) is a prevalent autosomal genetic disease associated with increased risk of early cardiovascular events and death due to chronic exposure to very high levels of low-density lipoprotein cholesterol (LDL-c). Pathogenic variants in the coding regions of LDLR, APOB and PCSK9 account for most FH cases, and variants in non-coding regions maybe involved in FH as well. Variants in the upstream region of LDLR, APOB and PCSK9 were screened by targeted next-generation sequencing and their effects were explored using in silico tools. Twenty-five patients without pathogenic variants in FH-related genes were selected. 3 kb upstream regions of LDLR, APOB and PCSK9 were sequenced using the AmpliSeq (Illumina) and Miseq Reagent Nano Kit v2 (Illumina). Sequencing data were analyzed using variant discovery and functional annotation tools. Potentially regulatory variants were selected by integrating data from public databases, published data and context-dependent regulatory prediction score. Thirty-four single nucleotide variants (SNVs) in upstream regions were identified (6 in LDLR, 15 in APOB, and 13 in PCSK9). Five SNVs were prioritized as potentially regulatory variants (rs934197, rs9282606, rs36218923, rs538300761, g.55038486A > G). APOB rs934197 was previously associated with increased rate of transcription, which in silico analysis suggests that could be due to reducing binding affinity of a transcriptional repressor. Our findings highlight the importance of variant screening outside of coding regions of all relevant genes. Further functional studies are necessary to confirm that prioritized variants could impact gene regulation and contribute to the FH phenotype.
Subject(s)
Receptors, LDL/genetics , Proprotein Convertase 9 , Apolipoproteins B/genetics , Phenotype , Hyperlipoproteinemia Type II/genetics , Cholesterol, LDL/genetics , Mutation , NucleotidesABSTRACT
ABSTRACT: Familial hypercholesterolemia (FH) is caused by deleterious mutations in the LDLR that increase markedly low-density lipoprotein (LDL) cholesterol and cause premature atherosclerotic cardiovascular disease. Functional effects of pathogenic LDLR variants identified in Brazilian FH patients were assessed using in vitro and in silico studies. Variants in LDLR and other FH-related genes were detected by exon-target gene sequencing. T-lymphocytes were isolated from 26 FH patients, and 3 healthy controls and LDLR expression and activity were assessed by flow cytometry and confocal microscopy. The impact of LDLR missense variants on protein structure was assessed by molecular modeling analysis. Ten pathogenic or likely pathogenic LDLR variants (six missense, two stop-gain, one frameshift, and one in splicing region) and six non-pathogenic variants were identified. Carriers of pathogenic and non-pathogenic variants had lower LDL binding and uptake in activated T-lymphocytes compared to controls (p < 0.05), but these variants did not influence LDLR expression on cell surface. Reduced LDL binding and uptake was also observed in carriers of LDLR null and defective variants. Modeling analysis showed that p.(Ala431Thr), p.(Gly549Asp) and p.(Gly592Glu) disturb intramolecular interactions of LDLR, and p.(Gly373Asp) and p.(Ile488Thr) reduce the stability of the LDLR protein. Docking and molecular interactions analyses showed that p.(Cys184Tyr) and p.(Gly373Asp) alter interaction of LDLR with Apolipoprotein B (ApoB). In conclusion, LDLR null and defective variants reduce LDL binding capacity and uptake in activated T-lymphocytes of FH patients and LDLR missense variants affect LDLR conformational stability and dissociation of the LDLR-ApoB complex, having a potential role in FH pathogenesis.
Subject(s)
T-Lymphocytes , Mutation, Missense , Hyperlipoproteinemia Type II , Lipoproteins, LDLABSTRACT
Resumo Fundamento A consolidação de novos paradigmas educacionais exige a implantação de estratégias inovadoras com potencial de transformar estudantes em profissionais competentes. Objetivos Analisar o conhecimento e a satisfação de estudantes antes e após a utilização de uma nova metodologia ativa de ensino médico de modelo digital humanizado chamada Virtual Case-Based Learning (VCBL). Métodos Estudo descritivo com análise documental sobre o processo de ensino-aprendizagem de estudantes de medicina. Dados obtidos da avaliação de conhecimento teórico e do instrumento de satisfação dos alunos nos anos de 2018 e 2019 foram analisados, e a nova metodologia proposta VCBL foi comparada com a metodologia ativa de ensino tradicional, o Problem-Based Learning (PBL). As análises descritivas e de associação foram realizadas utilizando o programa Statistical Package for the Social Sciences. Resultados Foram analisados 167 documentos aplicados a estudantes de medicina. Em relação à avaliação do conhecimento teórico, os alunos avaliados em 2018 obtiveram média 41,7%, comparados aos alunos de 2019 que alcançaram 73,3% (p<0,001). Entre os estudantes submetidos à avaliação da satisfação com a metodologia de aprendizagem proposta, 76,0% pontuaram o valor máximo para a questão um, e 83,0% para a questão número dois. Cerca de 70,0% dos estudantes classificaram positivamente o aprendizado adquirido após utilização da plataforma Paciente 360; 78,0% responderam que se sentem preparados para o atendimento ambulatorial; e 94,0% pontuaram de forma positiva a metodologia empregada. Conclusão Neste estudo inicial, os resultados indicaram que a nova ferramenta em metodologia ativa de ensino médico digital humanizado, o VCBL, pode auxiliar no aprimoramento do processo de ensino-aprendizagem, proporcionando conhecimento e satisfação dos estudantes.
Abstract Background The consolidation of new educational paradigms requires the implementation of innovative strategies to transform students into competent professionals. Objectives To assess knowledge and satisfaction of medical students before and after the use of a new humanized digital model of active learning, called virtual case-based learning (VCBL). Methods This was a descriptive, documentary analysis of the teaching-learning process of medical students. Data obtained from theoretical knowledge assessment and satisfaction evaluation questionnaires applied in 2018 and 2019 were analyzed, and the new VCBL was compared with the traditional active methodology PBL (problem-based learning). Descriptive and association analyses were made using the Statistical Package for the Social Sciences. Results A total of 167 evaluation forms administered to medical students were analyzed. In the evaluation of theoretical knowledge, the 2018 and the 2019 student groups had a mean of 41.7% and 73.3%, respectively (p<0.001). Among the students who responded to the satisfaction evaluation form, 76.0% gave the highest rating to question one, and 83.0% to question two. Nearly 70.0% of students positively evaluated knowledge acquisition with the Paciente 360 platform; 78.0% reported to feel prepared for working in outpatient care; and 94.0% positively evaluated the new method. Conclusion In this initial study, the results indicate that the new active method for humanized digital medical education, the VCBL, can help in the betterment of the teaching-learning process, promoting knowledge and satisfaction by the students.
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ABSTRACT: PCSK9 gain-of-function (GOF) variants increase degradation of low-density lipoprotein receptor (LDLR) and are potentially associated with Familial Hypercholesterolemia (FH). This study aimed to explore the effects of PCSK9 missense variants on protein structure and interactions with LDLR using molecular modeling analyses and in vitro functional studies. Variants in FH-related genes were identified in a Brazilian FH cohort using an exon-target gene sequencing strategy. Eight PCSK9 missense variants in pro- [p.(E32K) and p.(E57K)], catalytic [p.(R237W), p.(P279T) and p.(A443T)], and C-terminal histidine-cysteine rich (CHR) [p.(R469W), p.(Q619P) and p.(R680Q)] domains were identified. Molecular dynamics analyses revealed that GOF variants p.(E32K) and p.(R469W) increased extreme motions in PCSK9 amino acid backbone fluctuations and affected Hbond and water bridge interactions between the pro-domain and CM1 region of the CHR domain. HEK293FT cells transfected with plasmids carrying p.(E32K) and p.(R469W) variants reduced LDLR expression (8.7 % and 14.8 %, respectively) compared to wild type (p < 0.05) but these GOF variants did not affect PCSK9 expression and secretion. The missense variants p.(P279T) and p.(Q619P) also reduced protein stability and altered Hbond interactions. In conclusion, PCSK9 p.(E32K), p.(R469W), p.(P279T) and p.(Q619P) variants disrupt intramolecular interactions that are essential for PCSK9 structural conformation and biological activity and may have a potential role in FH pathogenesis.
Subject(s)
Humans , Mutation, Missense , Hyperlipoproteinemia Type II , Molecular Conformation , Proprotein Convertase 9 , Cholesterol, LDL/genetics , Cholesterol, LDL/metabolismABSTRACT
Statins are the first-line treatment for familial hypercholesterolemia (FH), but response is highly variable due to genetic and nongenetic factors. Here, we explored the association between response and genetic variability in 114 Brazilian adult FH patients. Specifically, a panel of 84 genes was analyzed by exon-targeted gene sequencing (ETGS), and the functional impact of variants in pharmacokinetic (PK) genes was assessed using an array of functionality prediction methods. Low-density lipoprotein cholesterol (LDL-c) response to statins (reduction ≥ 50%) and statin-related adverse event (SRAE) risk were assessed in carriers of deleterious variants in PK-related genes using multivariate linear regression analyses. Fifty-eight (50.8%) FH patients responded to statins, and 24 (21.0%) had SRAE. Results of the multivariate regression analysis revealed that ABCC1 rs45511401 significantly increased LDL-c reduction after statin treatment (p < 0.05). In silico analysis of the amino-acid change using molecular docking showed that ABCC1 rs45511401 possibly impairs statin efflux. Deleterious variants in PK genes were not associated with an increased risk of SRAE. In conclusion, the deleterious variant ABCC1 rs45511401 enhanced LDL-c response in Brazilian FH patients. As such, this variant might be a promising candidate for the individualization of statin therapy.
Subject(s)
Pharmacogenetics , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Drug-Related Side Effects and Adverse Reactions , Myalgia , Hyperlipoproteinemia Type IIABSTRACT
BACKGROUND: Familial hypercholesterolemia (FH) is a genetic disease that affects millions of people worldwide. OBJECTIVES: The study protocol FHBGEP was design to investigate the main genomic, epigenomic, and pharmacogenomic factors associated with FH and polygenic hypercholesterolemia (PH). METHODS: FH patients will be enrolled at six research centers in Brazil. An exon-targeted gene strategy will be used to sequence a panel of 84 genes related to FH, PH, pharmacogenomics and coronary artery disease. Variants in coding and regulatory regions will be identified using a proposed variant discovery pipeline and classified according to the American College Medical Genetics guidelines. Functional effects of variants in FH-related genes will be investigated by in vitro studies using lymphocytes and cell lines (HepG2, HUVEC and HEK293FT), CRISPR/Cas9 mutagenesis, luciferase reporter assay and other technologies. Functional studies in silico, such as molecular docking, molecular dynamics, and conformational analysis, will be used to explore the impact of novel variants on protein structure and function. DNA methylation profile and differential expression of circulating non-coding RNAs (miRNAs and lncRNAs) will be analyzed in FH patients and normolipidemic subjects (control group). The influence of genomic and epigenomic factors on metabolic and inflammatory status will be analyzed in FH patients. Pharmacogenomic studies will be conducted to investigate the influence of genomic and epigenomic factors on response to statins in FH patients. SUMMARY: The FHBGEP protocol has the potential to elucidate the genetic basis and molecular mechanisms involved in the pathophysiology of FH and PH, particularly in the Brazilian population. This pioneering approach includes genomic, epigenomic and functional studies, which results will contribute to the improvement of the diagnosis, prognosis and personalized therapy of FH patients.
Subject(s)
Pharmacogenetics , Coronary Artery Disease , Epigenomics , Genes , HypercholesterolemiaABSTRACT
Abstract: Statins are the most widely used cholesterol-lowering drugs for cardiovascular diseases prevention. However, some patients are refractory to treatment, whereas others experience statin-related adverse events (SRAE). It has been increasingly important to identify pharmacogenetic biomarkers for predicting statin response and adverse events. This case report describes a female patient with familial hypercholesterolemia (FH) who showed late response to rosuvastatin and experienced myalgia on statin treatment. In the first visit (V1), the patient reported myalgia to rosuvastatin 40 mg, which was interrupted for a 6-week wash-out period. In V2, rosuvastatin 20 mg was reintroduced, but her lipid profile did not show any changes after 6 weeks (V3) (LDL-c: 402 vs. 407 mg/dL). Her lipid profile markedly improved after 12 weeks of treatment (V4) (LDL-c: 208 mg/dL), suggesting a late rosuvastatin response. Her adherence to treatment was similar in V1 and V3 and no drug interactions were detected. Pharmacogenetic analysis revealed that the patient carries low-activity variants in SLCO1B1*1B and*5, SLCO1B3 (rs4149117 and rs7311358), and ABCB11 rs2287622, and the non-functional variant in CYP3A5*3. The combined effect of variants in pharmacokinetics-related genes may have contributed to the late response to rosuvastatin and statin-related myalgia. Therefore, they should be considered when assessing a patient's response to statin treatment. To the best of our knowledge, this is the first report of a pharmacogenetic analysis on a case of late rosuvastatin response.
Subject(s)
Pharmacogenetics , Hydroxymethylglutaryl-CoA Reductase Inhibitors , Precision Medicine , Myalgia , Hyperlipoproteinemia Type IIABSTRACT
INTRODUÇÃO: Os níveis de colesterol ligados à lipoproteína de alta densidade (HDL-c) estão inversamente associados a elevado risco de doenças cardiovasculares (DCV). Dentre as causas de baixos níveis de HDL-c está a deficiência familiar de lecitina-colesterol aciltransferase (LCAT), enzima responsável pela esterificação do colesterol livre na superfície de lipoproteínas; sua deficiência leva ao rápido catabolismo das apolipoproteínas AI e AII, principais constituintes do HDL. Existem duas formas de déficit de LCAT: familiar, caracterizada por opacidades corneanas, anemia hemolítica e insuficiência renal; e doença olho de peixe, quando ocorre em homozigose, cursando com baixos níveis de HDL-c, nefropatia e opacidades em córneas. A doença coronariana geralmente não faz parte do fenótipoda síndrome do olho de peixe, mas pode ocorrer em algumas mutações, mesmo em heterozigotos. MÉTODOS: Realizada pesquisa em SciELO e PubMed sobre o tema e revisão de prontuário. RESULTADOS (RELATO): Paciente 35 anos, feminino, com antecedentes de nefrolitíase e depressão, encaminhada para hospital terciário de cardiologia para investigação de síncope. Exame físico inicial evidenciou arcos corneanos bilaterais, sem outros achados. Tilt Test positivo para síncope cardioinibitória. Para investigação de achado em exame físico foram solicitados exames laboratoriais, sendo evidenciados colesterol total = 61, HDL-c=05 e LDL-c=44. Realizou tomografia para avaliação de escore de cálcio, com resultado normal. Fundo de olho documentou arco corneano em ambos os olhos e Van Herick IV bilateral (figura 1), sugerindo doença do olho de peixe. Em teste genético foi evidenciado variante no gene da LCAT, com troca de Arginina por Histidina na posição 246 (Arg246His), previamente associada a HDL-c baixo em famílias italiana e portuguesa, levando a um fenótipo similar à doença do olho de peixe, em geral não associado a DCV. Paciente mantém seguimento ambulatorial, sem evidências clínicas ou subclínicas de aterosclerose ou eventos cardiovasculares até o momento, função renal e acuidade visual normais. CONCLUSÃO: A doença do olho de peixe e suas variantes são raras e caracterizam-se por níveis extremamente baixos de HDL-c. O impacto quanto à elevação do risco cardiovascular ainda não é consenso na literatura. O diagnóstico torna-se importante para a pesquisa de aterosclerose subclínica, identificação e tratamento complicações e pesquisa da doença em familiares. No caso relatado, paciente diagnosticada com variante de doença do olho de peixe, sem evidências de aterosclerose até o momento.
Subject(s)
Genetics , Lecithin Cholesterol Acyltransferase DeficiencyABSTRACT
INTRODUÇÃO: A apolipoproteína A-V regula a produção e secreção de lipoproteína de densidade muito baixa (VLDL) pelo fígado, estimula a hidrólise de triglicerídeos (TG) mediada pela lipoproteína lipase (LPL) e atua na captação hepática de lipoproteínas ricas em TG e seus remanescentes. Alterações no gene APOA5 podem modificar a função e causar hipertrigliceridemia. Estudos in silico indicam que a variante rs3135506 c.56G>C pode diminuir a expressão de APOA5 e aumentar a secreção de VLDL. OBJETIVO: Investigar a influência da variante c.56G>C no perfil lipídico de indivíduos com hipercolesterolemia familial (HF). Métodos: Foram selecionados 35 indivíduos com diagnóstico clínico de HF segundo o critério Dutch-MEDPED e idade superior a 18 anos. Amostras de sangue foram obtidas para análise do perfil lipídico e sequenciamento. Dos 35 pacientes sequenciados, 22 obtiveram diagnóstico molecular para HF. Os éxons do APOA5 foram analisados por sequenciamento de alto rendimento utilizando a plataforma MiSeq (Illumina). As análises primária, secundária e terciária dos dados foram realizadas com os programas Real Time Analysis, MiSeq Reporter, BaseSpace Sequence Hub e VariantStudio. RESULTADOS: A variante rs3135506 foi detectada em 12 pacientes (Genótipo GC:34,3%). Os portadores do genótipo c.56GC tiveram maiores concentrações de TG e VLDL-c e menores de HDL-c que os portadores do genótipo c.56GG (Tabela 1). Os indivíduos HF foram categorizados segundo a presença ou não de hipertrigliceridemia (TG>150 mg/dL). A frequência do genótipo GC foi maior no grupo hipertrigliceridemia (8/15, 53,3%) que no grupo sem hipertrigliceridemia (4/20, 20,0%) (OR=4,57, IC95%:1,03-20,35, p=0,040). CONCLUSÃO: A variante APOA5 rs3135506 está associada a hipertrigliceridemia e HDL-c reduzido em indivíduos HF. (AU)