| 1. |
-
- 2019
-
Tidskriftsartikel (refereegranskat)
|
|
| 2. |
- Marouli, Eirini, et al.
(författare)
-
Rare and low-frequency coding variants alter human adult height
- 2017
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 542:7640, s. 186-190
-
Tidskriftsartikel (refereegranskat)abstract
- Height is a highly heritable, classic polygenic trait with approximately 700 common associated variants identified through genome-wide association studies so far. Here, we report 83 height-associated coding variants with lower minor-allele frequencies (in the range of 0.1-4.8%) and effects of up to 2 centimetres per allele (such as those in IHH, STC2, AR and CRISPLD2), greater than ten times the average effect of common variants. In functional follow-up studies, rare height increasing alleles of STC2 (giving an increase of 1-2 centimetres per allele) compromised proteolytic inhibition of PAPP-A and increased cleavage of IGFBP-4 in vitro, resulting in higher bioavailability of insulin-like growth factors. These 83 height-associated variants overlap genes that are mutated in monogenic growth disorders and highlight new biological candidates (such as ADAMTS3, IL11RA and NOX4) and pathways (such as proteoglycan and glycosaminoglycan synthesis) involved in growth. Our results demonstrate that sufficiently large sample sizes can uncover rare and low-frequency variants of moderate-to-large effect associated with polygenic human phenotypes, and that these variants implicate relevant genes and pathways.
|
|
| 3. |
- Turcot, Valerie, et al.
(författare)
-
Protein-altering variants associated with body mass index implicate pathways that control energy intake and expenditure in obesity
- 2018
-
Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 50:1, s. 26-41
-
Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies (GWAS) have identified >250 loci for body mass index (BMI), implicating pathways related to neuronal biology. Most GWAS loci represent clusters of common, noncoding variants from which pinpointing causal genes remains challenging. Here we combined data from 718,734 individuals to discover rare and low-frequency (minor allele frequency (MAF) < 5%) coding variants associated with BMI. We identified 14 coding variants in 13 genes, of which 8 variants were in genes (ZBTB7B, ACHE, RAPGEF3, RAB21, ZFHX3, ENTPD6, ZFR2 and ZNF169) newly implicated in human obesity, 2 variants were in genes (MC4R and KSR2) previously observed to be mutated in extreme obesity and 2 variants were in GIPR. The effect sizes of rare variants are similar to 10 times larger than those of common variants, with the largest effect observed in carriers of an MC4R mutation introducing a stop codon (p.Tyr35Ter, MAF = 0.01%), who weighed similar to 7 kg more than non-carriers. Pathway analyses based on the variants associated with BMI confirm enrichment of neuronal genes and provide new evidence for adipocyte and energy expenditure biology, widening the potential of genetically supported therapeutic targets in obesity.
|
|
| 4. |
- Kilpeläinen, Tuomas O, et al.
(författare)
-
Genome-wide meta-analysis uncovers novel loci influencing circulating leptin levels
- 2016
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Leptin is an adipocyte-secreted hormone, the circulating levels of which correlate closely with overall adiposity. Although rare mutations in the leptin (LEP) gene are well known to cause leptin deficiency and severe obesity, no common loci regulating circulating leptin levels have been uncovered. Therefore, we performed a genome-wide association study (GWAS) of circulating leptin levels from 32,161 individuals and followed up loci reaching P<10(-6) in 19,979 additional individuals. We identify five loci robustly associated (P<5 × 10(-8)) with leptin levels in/near LEP, SLC32A1, GCKR, CCNL1 and FTO. Although the association of the FTO obesity locus with leptin levels is abolished by adjustment for BMI, associations of the four other loci are independent of adiposity. The GCKR locus was found associated with multiple metabolic traits in previous GWAS and the CCNL1 locus with birth weight. Knockdown experiments in mouse adipose tissue explants show convincing evidence for adipogenin, a regulator of adipocyte differentiation, as the novel causal gene in the SLC32A1 locus influencing leptin levels. Our findings provide novel insights into the regulation of leptin production by adipose tissue and open new avenues for examining the influence of variation in leptin levels on adiposity and metabolic health.
|
|
| 5. |
- Wessel, Jennifer, et al.
(författare)
-
Low-frequency and rare exome chip variants associate with fasting glucose and type 2 diabetes susceptibility
- 2015
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 6
-
Tidskriftsartikel (refereegranskat)abstract
- Fasting glucose and insulin are intermediate traits for type 2 diabetes. Here we explore the role of coding variation on these traits by analysis of variants on the HumanExome BeadChip in 60,564 non-diabetic individuals and in 16,491 T2D cases and 81,877 controls. We identify a novel association of a low-frequency nonsynonymous SNV in GLP1R (A316T; rs10305492; MAF = 1.4%) with lower FG (beta = -0.09 +/- 0.01 mmol l(-1), P = 3.4 x 10(-12)), T2D risk (OR[95% CI] = 0.86[0.76-0.96], P = 0.010), early insulin secretion (beta = -0.07 +/- 0.035 pmol(insulin) mmol(glucose)(-1), P = 0.048), but higher 2-h glucose (beta = 0.16 +/- 0.05 mmol l(-1), P = 4.3 x 10(-4)). We identify a gene-based association with FG at G6PC2 (p(SKAT) = 6.8 x 10(-6)) driven by four rare protein-coding SNVs (H177Y, Y207S, R283X and S324P). We identify rs651007 (MAF = 20%) in the first intron of ABO at the putative promoter of an antisense lncRNA, associating with higher FG (beta = 0.02 +/- 0.004 mmol l(-1), P = 1.3 x 10(-8)). Our approach identifies novel coding variant associations and extends the allelic spectrum of variation underlying diabetes-related quantitative traits and T2D susceptibility.
|
|
| 6. |
|
|
| 7. |
- Berndt, Sonja I., et al.
(författare)
-
Genome-wide meta-analysis identifies 11 new loci for anthropometric traits and provides insights into genetic architecture
- 2013
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 45:5, s. 501-U69
-
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.
|
|
| 8. |
- Scott, Robert A., et al.
(författare)
-
Large-scale association analyses identify new loci influencing glycemic traits and provide insight into the underlying biological pathways
- 2012
-
Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 44:9, s. 991-1005
-
Tidskriftsartikel (refereegranskat)abstract
- Through genome-wide association meta-analyses of up to 133,010 individuals of European ancestry without diabetes, including individuals newly genotyped using the Metabochip, we have increased the number of confirmed loci influencing glycemic traits to 53, of which 33 also increase type 2 diabetes risk (q < 0.05). Loci influencing fasting insulin concentration showed association with lipid levels and fat distribution, suggesting impact on insulin resistance. Gene-based analyses identified further biologically plausible loci, suggesting that additional loci beyond those reaching genome-wide significance are likely to represent real associations. This conclusion is supported by an excess of directionally consistent and nominally significant signals between discovery and follow-up studies. Functional analysis of these newly discovered loci will further improve our understanding of glycemic control.
|
|
| 9. |
- Shungin, Dmitry, et al.
(författare)
-
Ranking and characterization of established BMI and lipid associated loci as candidates for gene-environment interactions
- 2017
-
Ingår i: PLOS Genetics. - : Public Library Science. - 1553-7390 .- 1553-7404. ; 13:6
-
Tidskriftsartikel (refereegranskat)abstract
- Phenotypic variance heterogeneity across genotypes at a single nucleotide polymorphism (SNP) may reflect underlying gene-environment (GxE) or gene-gene interactions. We modeled variance heterogeneity for blood lipids and BMI in up to 44,211 participants and investigated relationships between variance effects (P-v), GxE interaction effects (with smoking and physical activity), and marginal genetic effects (P-m). Correlations between P-v and P-m were stronger for SNPs with established marginal effects (Spearman's rho = 0.401 for triglycerides, and rho = 0.236 for BMI) compared to all SNPs. When P-v and P-m were compared for all pruned SNPs, only BMI was statistically significant (Spearman's rho = 0.010). Overall, SNPs with established marginal effects were overrepresented in the nominally significant part of the P-v distribution (P-binomial < 0.05). SNPs from the top 1% of the P-m distribution for BMI had more significant P-v values (Pmann-Whitney = 1.46x10(-5)), and the odds ratio of SNPs with nominally significant (< 0.05) P-m and P-v was 1.33 (95% CI: 1.12, 1.57) for BMI. Moreover, BMI SNPs with nominally significant GxE interaction P-values (Pint < 0.05) were enriched with nominally significant P-v values (P-binomial = 8.63x10(-9) and 8.52x10(-7) for SNP x smoking and SNP x physical activity, respectively). We conclude that some loci with strong marginal effects may be good candidates for GxE, and variance-based prioritization can be used to identify them.
|
|
| 10. |
- Krige, Adolf
(författare)
-
Sound, Light and Electricity : as applications and analysis techniques to study metabolic effect and biofilm characterization of Geobacter sulfurreducens
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ElectricityBio-electrochemical systems such as microbial fuel cells (MFCs) and microbial electrolysis cells have shown promise in wastewater treatment, bioremediation, desalination, carbon sequestration and as an alternative, renewable energy source. MFCs produces electricity via anaerobic oxidation of substrates with the subsequent extracellular electron transfer to an electrode. A wide variety of feedstocks have been researched, including various artificial and real wastewater sources as well as lignocellulosic material. Sweet sorghum, has been identified as a possible feedstock for electricity production in MFCs, using an anaerobic sludge inoculum, due to its high sugar content. To study sweet sorghum as an MFC feedstock a standard two chamber H-cell MFC was used, with an anaerobic sludge inoculum (Boden Biogas). A maximum voltage of 546±10 mV was obtained, and a maximum power and current density of 131±8 mW/m2 and 543±29 mA/m2 respectively. The substrate concentrations were monitored during the MFC operation, and the sugars were quickly fermented to volatile fatty acids which were then consumed during electricity generation. The power output was essentially independent of the substrate profile, with little difference between different VFAs. A more direct way was therefore needed to monitor the growth of an MFC biofilm as well as the effect of various substrates on extracellular electron transfer (EET). LightOne option for the direct monitoring of a biofilm is to use Raman spectroscopy to monitor the redox status of the biofilm, since Raman can be used to detect the redox state heme groups. Therefore, resonance Raman spectroscopy was chosen to monitor the cytochrome redox of Geobacter sulfurreducens, is a well know electroactive microorganism commonly found in mixed culture MFCs. G. sulfurreducensis able to produce thick, conductive biofilms as well as high current densities in MFCs. Due to the large variety of cytochromes present in G. sulfurreducens, it has various intricate and adaptable EET pathways, which makes the characterization of the essential EET components difficult. Due to the resonance of the cytochromes found in G. sulfurreducens it is possible to measure the redox state of the biofilm using resonance Raman spectroscopy. This was used for on-line monitoring of various G. sulfurreducens mutants during MFC operation (including the wild type PCA, the ii enhanced KN400 strain capable of higher current densities, and two deficient strains missing key cytochromes involved in the EET, i.e. ΔOmcS and ΔpilA). From this, the applicability of resonance Raman spectroscopy was shown to provide a non-destructive analytical tool for the in-situ monitoring of the oxidation state of proteins responsible for the EET process and the dynamics thereof. Resonance Raman with short integration times was further used, along with a dynamic model, to describe the dynamics of the EET pathways in the wild type as well as in an OmcS deficient strain during a stepped chronoamperometry measurement. This showed a significant difference in EET dynamics between ΔOmcS and the wild type, which was not detectible in the chronoamperometry data alone. The ΔOmcS biofilm showed a linearly decreasing trend in the reduced cytochrome concentration. This was likely caused by the saturation of a limiting mediator, resulting in an oxidation rate that was independent of the mediator concentration. The ΔOmcS biofilms response could, however, be better modelled using an empirical zeroth order model. This analytical method could prove valuable for the establishment of G. sulfurreducens as a chassis microorganism, allowing one to observe the effect of genetic modification on EET mechanisms.Sound Furthermore, to see if an abiotic factor such as sound can affect the functions in bacterial cells, we selected to study the effect of ultrasound on the growth of G. sulfurreducens. G. sulfurreducens is a key candidate for the development of a chassis organism in bioelectrochemical systems, and an external abiotic method of affecting growth or metabolite production could be extremely beneficial. For this, a well-defined sonobioreactor was developed and modelled to study the effect of ultrasound on G. sulfurreducens. This resulted in a significant increase in malate production during the exponential phase of planktonic growth (11 mmol when sonicated vs the 5 mmol control). Transcriptomics was then used to determine the reason for the observed increase. Although there was a large variance in the samples, this was possibly linked to the overexpression of glycosyltransferases, which are known to play a role in membrane stability and bind malate. Finally, a low-cost modification, which modifies a standard 3D printer into a bio-printer was developed to print artificial biofilms for bio-electrochemical systems. This was then used to print an artificial biofilm of G. sulfurreducens, significantly reducing the time required to produce an established biofilm
|
|
