| 51. |
- Artigas, MS, et al.
(författare)
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Sixteen new lung function signals identified through 1000 Genomes Project reference panel imputation
- 2015
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Ingår i: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6, s. 8658-
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Tidskriftsartikel (refereegranskat)abstract
- Lung function measures are used in the diagnosis of chronic obstructive pulmonary disease. In 38,199 European ancestry individuals, we studied genome-wide association of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC with 1000 Genomes Project (phase 1)-imputed genotypes and followed up top associations in 54,550 Europeans. We identify 14 novel loci (P<5 × 10−8) in or near ENSA, RNU5F-1, KCNS3, AK097794, ASTN2, LHX3, CCDC91, TBX3, TRIP11, RIN3, TEKT5, LTBP4, MN1 and AP1S2, and two novel signals at known loci NPNT and GPR126, providing a basis for new understanding of the genetic determinants of these traits and pulmonary diseases in which they are altered.
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| 52. |
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| 53. |
- Atabaki-Pasdar, Naeimeh, et al.
(författare)
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Statistical power considerations in genotype-based recall randomized controlled trials
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Randomized controlled trials (RCT) are often underpowered for validating gene-treatment interactions. Using published data from the Diabetes Prevention Program (DPP), we examined power in conventional and genotype-based recall (GBR) trials. We calculated sample size and statistical power for gene-metformin interactions (vs. placebo) using incidence rates, gene-drug interaction effect estimates and allele frequencies reported in the DPP for the rs8065082 SLC47A1 variant, a metformin transported encoding locus. We then calculated statistical power for interactions between genetic risk scores (GRS), metformin treatment and intensive lifestyle intervention (ILI) given a range of sampling frames, clinical trial sample sizes, interaction effect estimates, and allele frequencies; outcomes were type 2 diabetes incidence (time-to-event) and change in small LDL particles (continuous outcome). Thereafter, we compared two recruitment frameworks: GBR (participants recruited from the extremes of a GRS distribution) and conventional sampling (participants recruited without explicit emphasis on genetic characteristics). We further examined the influence of outcome measurement error on statistical power. Under most simulated scenarios, GBR trials have substantially higher power to observe gene-drug and gene-lifestyle interactions than same-sized conventional RCTs. GBR trials are becoming popular for validation of gene-treatment interactions; our analyses illustrate the strengths and weaknesses of this design.
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| 54. |
- Balliu, Brunilda, et al.
(författare)
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Genetic regulation of gene expression and splicing during a 10-year period of human aging
- 2019
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 20:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Molecular and cellular changes are intrinsic to aging and age-related diseases. Prior cross-sectional studies have investigated the combined effects of age and genetics on gene expression and alternative splicing; however, there has been no long-term, longitudinal characterization of these molecular changes, especially in older age.Results: We perform RNA sequencing in whole blood from the same individuals at ages 70 and 80 to quantify how gene expression, alternative splicing, and their genetic regulation are altered during this 10-year period of advanced aging at a population and individual level. We observe that individuals are more similar to their own expression profiles later in life than profiles of other individuals their own age. We identify 1291 and 294 genes differentially expressed and alternatively spliced with age, as well as 529 genes with outlying individual trajectories. Further, we observe a strong correlation of genetic effects on expression and splicing between the two ages, with a small subset of tested genes showing a reduction in genetic associations with expression and splicing in older age.Conclusions: These findings demonstrate that, although the transcriptome and its genetic regulation is mostly stable late in life, a small subset of genes is dynamic and is characterized by a reduction in genetic regulation, most likely due to increasing environmental variance with age.
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| 55. |
- Bandaru, Manoj Kumar, 1987-, et al.
(författare)
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Apoc2 mutant zebrafish: a model for hypertriglyceridemia and early-stage atherosclerosis
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Zebrafish larvae in a hypertriglyceridemic background can be useful to identify and characterize causal genes for triglyceride metabolism. A previous, small-scale study suggested that apolipoprotein C-II (apoc2)-mutant zebrafish larvae can be used to model hypertriglyceridemia-induced atherosclerosis. We aimed to replicate these findings in a large-scale study and asses if APOC-II may represent a useful therapeutic target. We generated apoc2 mutant zebrafish using CRISPR-Cas9 and examined cardiometabolomic traits in their offspring (F1 generation). Systematic characterization of 384 larvae using our image and assay-based, high-throughput pipeline showed that compound heterozygous larvae for loss of function mutations in apoc2 (n=35) have higher whole-body levels of triglycerides (0.71±0.16 SD), HDL cholesterol (0.32±0.15 SD) and total cholesterol (0.37±0.18 SD), and a trend for lower whole-body glucose levels (0.23±0.14 SD) compared with larvae without mutations in apoc2 (n=174). Such larvae also tended to have more vascular lipid deposition, however this effect did not reach significance (P=0.12). Interestingly, the trends for lower whole-body glucose levels and more vascular lipid deposition in larvae with anticipated loss of functional apoc2 reached significance when larvae (n=3812) from other screens, in which apoc2 was not experimentally perturbed were included as additional wildtype controls. Thus, our large-scale study confirms the role of apoc2 in hypertriglyceridemia and early-stage atherosclerosis. While apoc2 mutant zebrafish model can be used as a genetic background to identify and characterize causal genes for triglyceride metabolism, independent and opposite effects on triglycerides and glucose suggest that APOC-II is likely not a suitable target for prevention and treatment of coronary artery disease.
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| 56. |
- Bandaru, Manoj Kumar, 1987-, et al.
(författare)
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Image-based, in vivo characterization of cardiometabolic consequences of mutations in pcsk9
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Based on the association of loss-of-function mutations in proprotein convertase subtilisin/kexin type 9 (PCSK9) with low plasma LDL cholesterol levels, inhibition of the PCSK9 protein using monoclonal antibodies have emerged as an effective treatment option to lower LDL cholesterol levels and reduce the risk of coronary artery disease. Despite these beneficial effects, PCSK9 inhibitors may increase the risk of diabetes. In this study, we mimicked the mechanistic action of PCSK9 inhibitors in humans by inducing mutations in pcsk9 in zebrafish and examining their effects on dyslipidemia, early-stage atherosclerosis and diabetes-related traits in data from nearly 5000 zebrafish larvae. At 10 days of age, larvae with mutations in pcsk9 were characterized by lower whole-body LDL cholesterol levels (beta±SE -0.056±0.025 SD units) and protection against early-stage atherosclerosis, with less vascular lipid deposition (-0.133±0.035 SD) and less co-localization of macrophages with lipids (-0.086±0.032 SD). Mutant larvae also had fewer pancreatic β-cells (-0.153±0.055 SD). Thus, our findings in pcsk9 mutant larvae are in line with results from people carrying loss-of-function PCSK9 mutations, and are also in line with the effects of PCSK9 inhibitors in humans. Further, our results suggest that mutations in pcsk9 may increase the risk of diabetes through a direct effect on pancreatic β-cells.
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| 57. |
- Bandaru, Manoj Kumar, et al.
(författare)
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Zebrafish larvae as a model system for systematic characterization of drugs and genes in dyslipidemia and atherosclerosis
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hundreds of loci have been robustly associated with circulating lipids, atherosclerosis and coronary artery disease; but for most loci the causal genes and mechanisms remain uncharacterized.Methods: We developed a semi-automated experimental pipeline for systematic, quantitative, large-scale characterization of mechanisms, drugs and genes associated with dyslipidemia and atherosclerosis in a zebrafish model system. We validated our pipeline using a dietary (n>2000), drug treatment (n>1000), and genetic intervention (n=384).Results: Our results show that five days of overfeeding and cholesterol supplementation had independent pro-atherogenic effects, which could be diminished by concomitant treatment with atorvastatin and ezetimibe. CRISPR-Cas9-induced mutations in orthologues of proof-of-concept genes resulted in higher LDL cholesterol levels (apoea), and more early stage atherosclerosis (apobb.1).Conclusions: In summary, our pipeline facilitates systematic, in vivo characterization of drugs and candidate genes to increase our understanding of disease etiology, and can likely help identify novel targets for therapeutic intervention.
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| 58. |
- Bandaru, Manoj Kumar, 1987-
(författare)
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Zebrafish models for large-scale genetic screens in dyslipidemia and atherosclerosis : Validation and application
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hundreds of loci have been robustly associated with circulating lipids, atherosclerosis and coronary artery disease; but for most loci the causal genes and mechanisms remain uncharacterized. The overall aim of my thesis is to develop and validate novel in vivo model systems that are suitable for high-throughput, image-based genetic screens in coronary artery disease and related traits, and use these model systems to systematically characterize positional candidate genes.In Study I, I developed an experimental pipeline to validate the suitability of zebrafish larvae as a model system for systematic, large-scale characterization of drugs and genes associated with dyslipidemia and atherosclerosis. Using this pipeline, I showed that five days of overfeeding and cholesterol supplementation have independent pro-atherogenic effects in zebrafish larvae, which could be diminished by concomitant treatment with atorvastatin and ezetimibe. CRISPR-Cas9-induced mutations in orthologues of proof-of-concept genes resulted in higher LDL cholesterol levels (apoea), and more early stage atherosclerosis (apobb.1). Finally, the pipeline helped me to identify putative causal genes for circulating lipids and early-stage atherosclerosis (LPAR2 and GATAD2A).In Study II, I characterized cardiometabolic traits in apoc2 mutant zebrafish larvae and found that, similar to humans, larvae with two non-functional apoc2 alleles have higher whole-body levels of triglycerides and total cholesterol, and more vascular lipid deposition than larvae without mutations in apoc2. Interestingly, apoc2 mutant larvae also had lower glucose levels after adjusting for triglyceride levels, suggesting that therapeutic stimulation of apoc2 to prevent hypertriglyceridemia may result in hyperglycemia. Still, zebrafish larvae with mutations in apoc2 can be a useful model to identify and characterize additional causal genes for triglyceride metabolism.In Study III, I examined the effects of mutations in pcsk9 on atherosclerosis and diabetes-related traits in nearly 5,000 zebrafish larvae. Similar to the loss-of-function mutations in PCSK9 in humans, larvae with mutations in pcsk9 had lower LDLc levels and were protected from early-stage atherosclerosis. Interestingly, mutations in pcsk9 also resulted in fewer pancreatic β-cells in 10 days old larvae, which suggests the higher risk of diabetes in humans with mutations in PCSK9 may result from a direct effect on the beta cell.Based on these large-scale proof-of-concept studies, my thesis confirms that zebrafish larvae can be used for large-scale, systematic genetic screens in dyslipidemia and early-stage atherosclerosis.
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| 59. |
- Benedict, Christian, et al.
(författare)
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Fat Mass and Obesity-Associated Gene (FTO) Is Linked to Higher Plasma Levels of the Hunger Hormone Ghrelin and Lower Serum Levels of the Satiety Hormone Leptin in Older Adults
- 2014
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 63:11, s. 3955-3959
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Tidskriftsartikel (refereegranskat)abstract
- The mechanisms through which common polymorphisms in the fat mass and obesity-associated gene (FTO) drive the development of obesity in humans are poorly understood. Using cross-sectional data from 985 older people (50% females) who participated at age 70 years in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS), circulating levels of ghrelin and leptin were measured after an overnight fast. In addition, subjects were genotyped for FTO rs17817449 (AA, n = 345 [35%]; AC/CA, n = 481 [48.8%]; CC, n = 159 [16.1%]). Linear regression analyses controlling for sex, selfreported physical activity level, fasting plasma glucose, and BMI were used. A positive relationship between the number of FTO C risk alleles and plasma ghrelin levels was found (P = 0.005; relative plasma ghrelin difference between CC and AA carriers = similar to 9%). In contrast, serum levels of the satiety-enhancing hormone leptin were inversely linked to the number of FTO C risk alleles (P = 0.001; relative serum leptin difference between CC and AA carriers = similar to 11%). These associations were also found when controlling for waist circumference. The present findings suggest that FTO may facilitate weight gain in humans by shifting the endocrine balance from the satiety hormone leptin toward the hunger-promoting hormone ghrelin.
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| 60. |
- Berndt, Sonja I., et al.
(författare)
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Genome-wide meta-analysis identifies 11 new loci for anthropometric traits and provides insights into genetic architecture
- 2013
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:5, s. 501-U69
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Tidskriftsartikel (refereegranskat)abstract
- Approaches exploiting trait distribution extremes may be used to identify loci associated with common traits, but it is unknown whether these loci are generalizable to the broader population. In a genome-wide search for loci associated with the upper versus the lower 5th percentiles of body mass index, height and waist-to-hip ratio, as well as clinical classes of obesity, including up to 263,407 individuals of European ancestry, we identified 4 new loci (IGFBP4, H6PD, RSRC1 and PPP2R2A) influencing height detected in the distribution tails and 7 new loci (HNF4G, RPTOR, GNAT2, MRPS33P4, ADCY9, HS6ST3 and ZZZ3) for clinical classes of obesity. Further, we find a large overlap in genetic structure and the distribution of variants between traits based on extremes and the general population and little etiological heterogeneity between obesity subgroups.
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