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Berulava T, Ziehe M, Klein-Hitpass L, Mladenov E, Thomale J, Rüther U, Horsthemke B. FTO levels affect RNA modification and the transcriptome. Eur J Hum Genet 2012; 21:317-23. [PMID: 22872099 DOI: 10.1038/ejhg.2012.168] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
A block of single-nucleotide polymorphisms within intron 1 of the FTO (fat mass and obesity associated) gene is associated with variation in body weight. Previous works suggest that increased expression of FTO, which encodes a 2-oxoglutarate-dependent nucleic acid demethylase, leads to increased body weight, although the underlying mechanism has remained unclear. To elucidate the function of FTO, we examined the consequences of altered FTO levels in cultured cells and murine brain. Here we show that a knockdown of FTO in HEK293 cells affects the transcripts levels of genes involved in the response to starvation, whereas overexpression of FTO affects the transcript levels of genes related to RNA processing and metabolism. Subcellular localization of FTO further strengthens the latter notion. Using immunocytochemistry and confocal laser scanning microscopy, we detected FTO in nuclear speckles and--to a lesser and varying extent--in the nucleoplasm and nucleoli of HEK293, HeLa and MCF-7 cells. Moreover, RNA modification analyses revealed that loss of Fto affects the 3-methyluridine/uridine and pseudouridine/uridine ratios in total brain RNA. We conclude that altered levels of FTO have multiple and diverse consequences on RNA modifications and the transcriptome.
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Affiliation(s)
- Tea Berulava
- Institut für Humangenetik, Universitätsklinikum Essen, Essen, Germany
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102
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Livshits G, Malkin I, Moayyeri A, Spector TD, Hammond CJ. Association of FTO gene variants with body composition in UK twins. Ann Hum Genet 2012; 76:333-41. [PMID: 22817777 PMCID: PMC3532623 DOI: 10.1111/j.1469-1809.2012.00720.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The association of FTO gene variants with body mass index (BMI) and other obesity characteristics is well established. However, uncertainties remain whether the association is present only in young populations and whether it is attributable to body fat mass specifically. We aimed to clarify these two questions in a large sample (N= 4,523 individuals) of middle-aged and older (range 40–80 years) British female twins. The women were assessed for BMI, waist and hip circumference, total lean (LBM) and fat (FBM) body mass. Since the majority of FTO association signals have been reported in a haploblock bordering 52,355–52,408 kb (on chromosome 16q12.2), we examined five genotyped and 43 imputed SNPs mapped to this block. Canonical correlation and other association analyses showed significant and consistent association between the selected SNP and studied body composition phenotypes, with p-values reaching p= 0.000004. Of particular interest, in addition to the expected significant associations between FTO variants and FBM, we also identified significant associations with LBM. These results suggest that the association between FTO variants and body composition phenotypes is present across a wide range of ages, and that FTO appears primarily to affect the amount of body soft tissue, influencing both fat and lean mass.
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Affiliation(s)
- Gregory Livshits
- Department of Twin Research and Genetic Epidemiology, King's College London, UK
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103
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Kowalska I, Adamska A, Malecki MT, Karczewska-Kupczewska M, Nikolajuk A, Szopa M, Gorska M, Straczkowski M. Impact of the FTO gene variation on fat oxidation and its potential influence on body weight in women with polycystic ovary syndrome. Clin Endocrinol (Oxf) 2012; 77:120-5. [PMID: 22385136 DOI: 10.1111/j.1365-2265.2012.04379.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
CONTEXT Polycystic ovary syndrome (PCOS) is a heterogeneous disorder where insulin resistance might be involved in the development of endocrine and metabolic abnormalities. It has recently been shown that the FTO gene modifies weight, fat mass and insulin sensitivity in women with PCOS, where its role might be larger than in other phenotypes. OBJECTIVE The aim of this study was to estimate the effect of a variation of the FTO gene on carbohydrate and lipid oxidation in PCOS women. PATIENTS The study group consisted of 65 women with PCOS and 28 healthy, normally menstruating women. MEASUREMENTS Clinical examination, anthropometric measurements, euglycaemic hyperinsulinaemic clamp and measurements of serum sex hormones were performed. Carbohydrate and lipid oxidation were evaluated with indirect calorimetry in the baseline state and during last 30 min of the clamp. The FTO rs9939609 polymorphism was genotyped using the restriction fragment length polymorphism method. RESULTS There were no differences in carbohydrate and lipid oxidation between PCOS and control women. In the PCOS group, TT homozygotes had higher baseline fat oxidation in comparison with carriers of the A allele (P = 0·018), which was not found in the control group. We did not observe the effect of the FTO gene variation on insulin-stimulated lipid oxidation and neither on the baseline nor on the insulin-stimulated carbohydrate oxidation. CONCLUSION Our data show that this FTO gene variation might influence the baseline lipid oxidation in PCOS patients. This might potentially be one of the mechanisms explaining the impact of the FTO gene on body weight in PCOS.
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Affiliation(s)
- Irina Kowalska
- Department of Endocrinology, Diabetology and Internal Medicine, Medical University of Białystok, Białystok, Poland.
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Pitman RT, Fong JT, Billman P, Puri N. Knockdown of the fat mass and obesity gene disrupts cellular energy balance in a cell-type specific manner. PLoS One 2012; 7:e38444. [PMID: 22675562 PMCID: PMC3367022 DOI: 10.1371/journal.pone.0038444] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Accepted: 05/08/2012] [Indexed: 11/19/2022] Open
Abstract
Recent studies suggest that FTO variants strongly correlate with obesity and mainly influence energy intake with little effect on the basal metabolic rate. We suggest that FTO influences eating behavior by modulating intracellular energy levels and downstream signaling mechanisms which control energy intake and metabolism. Since FTO plays a particularly important role in adipocytes and in hypothalamic neurons, SH-SY5Y neuronal cells and 3T3-L1 adipocytes were used to understand how siRNA mediated knockdown of FTO expression alters cellular energy homeostasis. Cellular energy status was evaluated by measuring ATP levels using a luminescence assay and uptake of fluorescent glucose. FTO siRNA in SH-SY5Y cells mediated mRNA knockdown (−82%), increased ATP concentrations by up to 46% (P = 0.013) compared to controls, and decreased phosphorylation of AMPk and Akt in SH-SY5Y by −52% and −46% respectively as seen by immunoblotting. In contrast, FTO siRNA in 3T3-L1 cells decreased ATP concentration by −93% (p<0.0005), and increased AMPk and Akt phosphorylation by 204% and 70%, respectively suggesting that FTO mediates control of energy levels in a cell-type specific manner. Furthermore, glucose uptake was decreased in both SH-SY5Y (−51% p = 0.015) and 3T3-L1 cells (−30%, p = 0.0002). We also show that FTO knockdown decreases NPY mRNA expression in SH-SY5Y cells (−21%) through upregulation of pSTAT3 (118%). These results provide important evidence that FTO-variant linked obesity may be associated with altered metabolic functions through activation of downstream metabolic mediators including AMPk.
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Affiliation(s)
- Ryan T. Pitman
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America
| | - Jason T. Fong
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America
| | - Penny Billman
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America
| | - Neelu Puri
- Department of Biomedical Sciences, University of Illinois College of Medicine, Rockford, Illinois, United States of America
- * E-mail:
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105
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Emerging roles for TNIP1 in regulating post-receptor signaling. Cytokine Growth Factor Rev 2012; 23:109-18. [PMID: 22542476 DOI: 10.1016/j.cytogfr.2012.04.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/29/2012] [Accepted: 04/06/2012] [Indexed: 02/08/2023]
Abstract
A vast number of cellular processes and signaling pathways are regulated by various receptors, ranging from transmembrane to nuclear receptors. These receptor-mediated processes are modulated by a diverse set of regulatory proteins. TNFα-induced protein 3-interacting protein 1 is such a protein that inhibits both transduction by transmembrane receptors, such as TNFα-receptor, EGF-R, and TLR, and nuclear receptors' PPAR and RAR activity. These receptors play key roles in regulating inflammation and inflammatory diseases. A growing number of references have implicated TNIP1 through GWAS and expression studies in chronic inflammatory diseases such as psoriasis and rheumatoid arthritis, although TNIP1s exact role has yet been determined. In this review, we aim to integrate the current knowledge of TNIP1s functions with the diseases in which it has been associated to potentially elucidate the role this regulator has in promoting or alleviating these inflammatory diseases.
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Sällman Almén M, Rask-Andersen M, Jacobsson JA, Ameur A, Kalnina I, Moschonis G, Juhlin S, Bringeland N, Hedberg LA, Ignatovica V, Chrousos GP, Manios Y, Klovins J, Marcus C, Gyllensten U, Fredriksson R, Schiöth HB. Determination of the obesity-associated gene variants within the entire FTO gene by ultra-deep targeted sequencing in obese and lean children. Int J Obes (Lond) 2012; 37:424-31. [PMID: 22531089 PMCID: PMC3595467 DOI: 10.1038/ijo.2012.57] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND The Fat mass and obesity-associated gene (FTO) was the first gene reliably associated with body mass index in genome-wide association studies on a population level. At present, the genetic variations within the FTO gene are still the common variants that have the largest influence on body mass index. METHODS In the current study, we amplified the entire FTO gene, in total 412 Kbp, in over 200 long-range PCR fragments from each individual, from 524 severely obese and 527 lean Swedish children, and sequenced the products as two DNA pools using massive parallel sequencing (SOLiD). RESULTS The sequencing achieved very high coverage (median 18 000 reads) and we detected and estimated allele frequencies for 705 single nucleotide polymorphisms (SNPs) (19 novel) and 40 indels (24 novel) using a sophisticated statistical approach to remove false-positive SNPs. We identified 19 obesity-associated SNPs within intron one of the FTO gene, and validated our findings with genotyping. Ten of the validated obesity-associated SNPs have a stronger obesity association (P<0.007) than the commonly studied rs9939609 SNP (P<0.012). CONCLUSIONS This study provides a comprehensive obesity-associated variation map of FTO, identifies novel lead SNPs and evaluates putative causative variants. We conclude that intron one is the only region within the FTO gene associated with obesity, and finally, we establish next generation sequencing of pooled DNA as a powerful method to investigate genetic association with complex diseases and traits.
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Affiliation(s)
- M Sällman Almén
- Department of Neuroscience, Functional Pharmacology, Uppsala University, BMC, Uppsala, Sweden
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107
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Heritability of body mass index in pre-adolescence, young adulthood and late adulthood. Eur J Epidemiol 2012; 27:247-53. [PMID: 22426805 DOI: 10.1007/s10654-012-9678-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 03/07/2012] [Indexed: 10/28/2022]
Abstract
Increased body mass index (BMI) is a worldwide health issue. Individual differences in the susceptibility to increased BMI could be related to genes or environment. We performed a systematic review of genetic studies on BMI in pre-adolescence, young adulthood and late adulthood. We searched PubMed and EMBASE with heritability, body mass index, BMI, weight, height, anthropometry and twins as search terms. Studies reporting intra-pair correlations of healthy twin pairs that were raised together were included. This resulted in the inclusion of 8,179 monozygotic (MZ) and 9,977 dizygotic (DZ) twin pairs from twelve published studies in addition to individual participant data for 629 MZ and 594 DZ pairs from four twin registries. Structural equation modelling with intra-pair twin correlations showed that the heritability of BMI remained high over all age categories ranging from 61% (95% CI 54-64%) to 80% (95% CI 76-81%) for male and female subjects combined, while unique environmental influences increased from 14% (95% CI 13-15%) to 40% (95% CI 37-43%) with increasing age. Heritability of BMI remains consistently high over different age categories. Environmental changes over time do not seem to have as big a relative impact on an individual's weight as previously reported, suggesting a mainly genetic influence on variation in BMI over the years.
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108
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The A-allele of the common FTO gene variant rs9939609 complicates weight maintenance in severe obese patients. Int J Obes (Lond) 2012; 37:135-9. [PMID: 22310469 DOI: 10.1038/ijo.2012.14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The A-allele of the fat mass and obesity-associated (FTO) gene variant rs9939609 has been associated with increased body weight, whereas no effect on weight loss during weight reduction programs has been observed. We questioned whether the AA-genotype interferes with weight stabilization after weight loss. DESIGN We conducted a monocentric, longitudinal study involving obese individuals. The FTO gene variant rs9939609 was genotyped in participants attending a weight reduction program that was divided into two phases: a weight reduction period with formula diet (12 weeks) and a weight maintenance phase (40 weeks). Body weight, body mass index (BMI), blood pressure and concentrations of blood glucose, total cholesterol, low-density lipoprotein, high-density lipoprotein and triglycerides were determined in week 0 (T(0)), after 12 weeks (T(1)) and at the end in week 52 (T(2)). SUBJECTS A total of 193 obese subjects aged between 18 and 72 years (129 female, 64 male; initial body weight: 122.4±22.3 kg, initial BMI: 41.8±6.7 kg m(-2)) were included. RESULTS Genotyping revealed 32.1% TT-, 39.4% AT- and 28.5% AA-genotype carriers. At T (0), carriers of the AA-genotype had significantly higher body weight (P=0.04) and BMI (P=0.005) than carriers of the TT-genotype. Of the 193 participants, 68 discontinued and 125 completed the program. Dropout rate was not influenced by genotype (P=0.33). Completers with AA-genotype showed significantly lower additional weight loss during the weight maintenance phase than TT-genotype carriers (P=0.02). Furthermore, among participants facing weight regain during weight maintenance (n=52), more subjects were carrying the AA-genotype (P=0.006). No influence of genotype on weight reduction under formula diet was observed (P=0.32). CONCLUSION In this program, the AA-genotype of rs9939609 was associated with a higher initial body weight and did influence success of weight stabilization. Thus, emphasizing the maintenance phase during a weight reduction program might result in better success for AA-genotype carriers.
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Rask-Andersen M, Almén MS, Olausen HR, Olszewski PK, Eriksson J, Chavan RA, Levine AS, Fredriksson R, Schiöth HB. Functional coupling analysis suggests link between the obesity gene FTO and the BDNF-NTRK2 signaling pathway. BMC Neurosci 2011; 12:117. [PMID: 22087873 PMCID: PMC3248879 DOI: 10.1186/1471-2202-12-117] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 11/16/2011] [Indexed: 11/24/2022] Open
Abstract
Background The Fat mass and obesity gene (FTO) has been identified through genome wide association studies as an important genetic factor contributing to a higher body mass index (BMI). However, the molecular context in which this effect is mediated has yet to be determined. We investigated the potential molecular network for FTO by analyzing co-expression and protein-protein interaction databases, Coxpresdb and IntAct, as well as the functional coupling predicting multi-source database, FunCoup. Hypothalamic expression of FTO-linked genes defined with this bioinformatics approach was subsequently studied using quantitative real time-PCR in mouse feeding models known to affect FTO expression. Results We identified several candidate genes for functional coupling to FTO through database studies and selected nine for further study in animal models. We observed hypothalamic expression of Profilin 2 (Pfn2), cAMP-dependent protein kinase catalytic subunit beta (Prkacb), Brain derived neurotrophic factor (Bdnf), neurotrophic tyrosine kinase, receptor, type 2 (Ntrk2), Signal transducer and activator of transcription 3 (Stat3), and Btbd12 to be co-regulated in concert with Fto. Pfn2 and Prkacb have previously not been linked to feeding regulation. Conclusions Gene expression studies validate several candidates generated through database studies of possible FTO-interactors. We speculate about a wider functional role for FTO in the context of current and recent findings, such as in extracellular ligand-induced neuronal plasticity via NTRK2/BDNF, possibly via interaction with the transcription factor CCAAT/enhancer binding protein β (C/EBPβ).
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Affiliation(s)
- Mathias Rask-Andersen
- Department of Neuroscience, Functional Pharmacology, Uppsala University, BMC, Uppsala SE 75124, Sweden
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Association of TMEM18 variants with BMI and waist circumference in children and correlation of mRNA expression in the PFC with body weight in rats. Eur J Hum Genet 2011; 20:192-7. [PMID: 21952719 DOI: 10.1038/ejhg.2011.176] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Genome-wide association studies have shown a strong association of single-nucleotide polymorphisms (SNPs) in the near vicinity of the TMEM18 gene. The effects of the TMEM18-associated variants are more readily observed in children. TMEM18 encodes a 3TM protein, which locates to the nuclear membrane. The functional context of TMEM18 and the effects of its associated variants are as of yet undetermined. To further explore the effects of near-TMEM18 variants, we have genotyped two TMEM18-associated SNPs, rs6548238 and rs4854344, in a cohort of 2352 Greek children (Healthy Growth Study). Included in this study are data on anthropomorphic traits body weight, BMI z-score and waist circumference. Also included are dietary energy and macronutrient intake as measured via 24-h recall interviews. Major alleles of rs6548238 and rs4854344 were significantly associated with an increased risk of obesity (odds ratio = 1.489 (1.161-1.910) and 1.494 (1.165-1.917), respectively), and positively correlated to body weight (P = 0.017, P = 0.010) and waist circumference (P = 0.003, P = 0.003). An association to energy and macronutrient intake was not observed in this cohort. We also correlated food intake and body weight in a food choice model in rats to Tmem18 expression in central regions involved in feeding behavior. We observed a strong positive correlation between TMEM18 expression and body weight in the prefrontal cortex (PFC) (r = 0.5694, P = 0.0003) indicating a potential role for TMEM18 in higher functions related to feeding involving the PFC.
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Abstract
Genome-wide association studies have been very powerful, uncovering potentially new biology that would not have been possible using a candidate gene approach. A prime example of this is the gene FTO (fat mass and obesity associated), which first came to light in 2007, when single nucleotide polymorphisms in its first intron were robustly associated with body mass index and obesity. Subsequently, as it became clear that this association with body weight, and increasingly food intake, was replicable across multiple populations and different age groups, attention was turned to studying the biology of FTO, about which absolutely nothing was known. This review focuses on the genetic and biochemical approaches as well as animal models that have been used by us and others since 2007 to try and uncover the complex biology of FTO.
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Affiliation(s)
- Yi-Chun Loraine Tung
- University of Cambridge Metabolic Research Labs, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
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112
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Hertel JK, Johansson S, Sonestedt E, Jonsson A, Lie RT, Platou CG, Nilsson PM, Rukh G, Midthjell K, Hveem K, Melander O, Groop L, Lyssenko V, Molven A, Orho-Melander M, Njølstad PR. FTO, type 2 diabetes, and weight gain throughout adult life: a meta-analysis of 41,504 subjects from the Scandinavian HUNT, MDC, and MPP studies. Diabetes 2011; 60:1637-44. [PMID: 21398525 PMCID: PMC3292341 DOI: 10.2337/db10-1340] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE FTO is the most important polygene identified for obesity. We aimed to investigate whether a variant in FTO affects type 2 diabetes risk entirely through its effect on BMI and how FTO influences BMI across adult life span. RESEARCH DESIGN AND METHODS Through regression models, we assessed the relationship between the FTO single nucleotide polymorphisms rs9939609, type 2 diabetes, and BMI across life span in subjects from the Norwegian population-based HUNT study using cross-sectional and longitudinal perspectives. For replication and meta-analysis, we used data from the Malmö Diet and Cancer (MDC) and Malmö Preventive Project (MPP) cohorts, comprising a total sample of 41,504 Scandinavians. RESULTS The meta-analysis revealed a highly significant association for rs9939609 with both type 2 diabetes (OR 1.13; P = 4.5 × 10(-8)) and the risk to develop incident type 2 diabetes (OR 1.16; P = 3.2 × 10(-8)). The associations remained also after correction for BMI and other anthropometric measures. Furthermore, we confirmed the strong effect on BMI (0.28 kg/m(2) per risk allele; P = 2.0 × 10(-26)), with no heterogeneity between different age-groups. We found no differences in change of BMI over time according to rs9939609 risk alleles, neither overall (ΔBMI = 0.0 [-0.05, 0.05]) nor in any individual age stratum, indicating no further weight gain attributable to FTO genotype in adults. CONCLUSIONS We have identified that a variant in FTO alters type 2 diabetes risk partly independent of its observed effect on BMI. The additional weight gain as a result of the FTO risk variant seems to occur before adulthood, and the BMI difference remains stable thereafter.
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Affiliation(s)
- Jens K. Hertel
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Stefan Johansson
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Emily Sonestedt
- Department of Clinical Sciences in Malmö, Nutrition Epidemiology, Lund University, Malmö, Sweden
- Department of Clinical Sciences in Malmö, Diabetes and Cardiovascular Disease–Genetic Epidemiology, Lund University, Malmö, Sweden
| | - Anna Jonsson
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University, and Lund University Diabetes Centre, Malmö, Sweden
| | - Rolv T. Lie
- Department of Public Health and Primary Health Care, University of Bergen, Bergen, Norway
| | - Carl G.P. Platou
- HUNT Research Centre, Department of Public Health and General Practice, Norwegian University of Science and Technology, Verdal, Norway
- Department of Internal Medicine, Levanger Hospital, Nord-Trøndelag Health Trust, Norway
| | - Peter M. Nilsson
- Department of Clinical Sciences, Division of Medicine, Lund University, Malmö, Sweden
| | - Gull Rukh
- Department of Clinical Sciences in Malmö, Diabetes and Cardiovascular Disease–Genetic Epidemiology, Lund University, Malmö, Sweden
| | - Kristian Midthjell
- HUNT Research Centre, Department of Public Health and General Practice, Norwegian University of Science and Technology, Verdal, Norway
| | - Kristian Hveem
- HUNT Research Centre, Department of Public Health and General Practice, Norwegian University of Science and Technology, Verdal, Norway
| | - Olle Melander
- Department of Clinical Sciences, Hypertension and Cardiovascular Diseases, University Hospital Malmö, Lund University, Malmö, Sweden
| | - Leif Groop
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University, and Lund University Diabetes Centre, Malmö, Sweden
- Department of Medicine, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Valeriya Lyssenko
- Department of Clinical Sciences, Diabetes and Endocrinology, Lund University, and Lund University Diabetes Centre, Malmö, Sweden
| | - Anders Molven
- Gade Institute, University of Bergen, Bergen, Norway
- Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Marju Orho-Melander
- Department of Clinical Sciences in Malmö, Diabetes and Cardiovascular Disease–Genetic Epidemiology, Lund University, Malmö, Sweden
| | - Pål R. Njølstad
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Pediatrics, Haukeland University Hospital, Bergen, Norway
- Corresponding author: Pål R. Njølstad,
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113
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Cox RD, Church CD. Mouse models and the interpretation of human GWAS in type 2 diabetes and obesity. Dis Model Mech 2011; 4:155-64. [PMID: 21324932 PMCID: PMC3046087 DOI: 10.1242/dmm.000414] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Within the last 3 years, genome-wide association studies (GWAS) have had unprecedented success in identifying loci that are involved in common diseases. For example, more than 35 susceptibility loci have been identified for type 2 diabetes and 32 for obesity thus far. However, the causal gene and variant at a specific linkage disequilibrium block is often unclear. Using a combination of different mouse alleles, we can greatly facilitate the understanding of which candidate gene at a particular disease locus is associated with the disease in humans, and also provide functional analysis of variants through an allelic series, including analysis of hypomorph and hypermorph point mutations, and knockout and overexpression alleles. The phenotyping of these alleles for specific traits of interest, in combination with the functional analysis of the genetic variants, may reveal the molecular and cellular mechanism of action of these disease variants, and ultimately lead to the identification of novel therapeutic strategies for common human diseases. In this Commentary, we discuss the progress of GWAS in identifying common disease loci for metabolic disease, and the use of the mouse as a model to confirm candidate genes and provide mechanistic insights.
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Affiliation(s)
- Roger D Cox
- Metabolism and Inflammation, MRC Harwell Mammalian Genetics Unit, Harwell Science and Innovation Campus, Oxfordshire, UK.
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114
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Lurie G, Gaudet MM, Spurdle AB, Carney ME, Wilkens LR, Yang HP, Weiss NS, Webb PM, Thompson PJ, Terada K, Setiawan VW, Rebbeck TR, Prescott J, Orlow I, O'Mara T, Olson SH, Narod SA, Matsuno RK, Lissowska J, Liang X, Levine DA, Le Marchand L, Kolonel LN, Henderson BE, Garcia-Closas M, Doherty JA, De Vivo I, Chen C, Brinton LA, Akbari MR, Goodman MT. The obesity-associated polymorphisms FTO rs9939609 and MC4R rs17782313 and endometrial cancer risk in non-Hispanic white women. PLoS One 2011; 6:e16756. [PMID: 21347432 PMCID: PMC3035652 DOI: 10.1371/journal.pone.0016756] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/30/2010] [Indexed: 01/14/2023] Open
Abstract
Overweight and obesity are strongly associated with endometrial cancer. Several independent genome-wide association studies recently identified two common polymorphisms, FTO rs9939609 and MC4R rs17782313, that are linked to increased body weight and obesity. We examined the association of FTO rs9939609 and MC4R rs17782313 with endometrial cancer risk in a pooled analysis of nine case-control studies within the Epidemiology of Endometrial Cancer Consortium (E2C2). This analysis included 3601 non-Hispanic white women with histologically-confirmed endometrial carcinoma and 5275 frequency-matched controls. Unconditional logistic regression models were used to assess the relation of FTO rs9939609 and MC4R rs17782313 genotypes to the risk of endometrial cancer. Among control women, both the FTO rs9939609 A and MC4R rs17782313 C alleles were associated with a 16% increased risk of being overweight (p = 0.001 and p = 0.004, respectively). In case-control analyses, carriers of the FTO rs9939609 AA genotype were at increased risk of endometrial carcinoma compared to women with the TT genotype [odds ratio (OR) = 1.17; 95% confidence interval (CI): 1.03–1.32, p = 0.01]. However, this association was no longer apparent after adjusting for body mass index (BMI), suggesting mediation of the gene-disease effect through body weight. The MC4R rs17782313 polymorphism was not related to endometrial cancer risk (per allele OR = 0.98; 95% CI: 0.91–1.06; p = 0.68). FTO rs9939609 is a susceptibility marker for white non-Hispanic women at higher risk of endometrial cancer. Although FTO rs9939609 alone might have limited clinical or public health significance for identifying women at high risk for endometrial cancer beyond that of excess body weight, further investigation of obesity-related genetic markers might help to identify the pathways that influence endometrial carcinogenesis.
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Affiliation(s)
- Galina Lurie
- Cancer Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, United States of America
- * E-mail:
| | - Mia M. Gaudet
- Epidemiology Research Program, American Cancer Society, Inc., Atlanta, Georgia, United States of America
| | - Amanda B. Spurdle
- Queensland Institute of Medical Research, Brisbane, Post Office Royal Brisbane Hospital, Brisbane, Australia
| | - Michael E. Carney
- Department of Obstetrics and Gynecology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Lynne R. Wilkens
- Cancer Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Hannah P. Yang
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America
| | - Noel S. Weiss
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, United States of America
- Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Penelope M. Webb
- Queensland Institute of Medical Research, Brisbane, Post Office Royal Brisbane Hospital, Brisbane, Australia
| | - Pamela J. Thompson
- Cancer Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Keith Terada
- Department of Obstetrics and Gynecology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Veronica Wendy Setiawan
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Timothy R. Rebbeck
- University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- Abramson Cancer Center, Philadelphia, Pennsylvania, United States of America
| | - Jennifer Prescott
- Department of Epidemiology, Program in Molecular and Genetic Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Irene Orlow
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Tracy O'Mara
- Queensland Institute of Medical Research, Brisbane, Post Office Royal Brisbane Hospital, Brisbane, Australia
- Hormone Dependent Cancer Group, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Sara H. Olson
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Steven A. Narod
- Women's College Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Rayna K. Matsuno
- Cancer Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, United States of America
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Jolanta Lissowska
- Department of Cancer Epidemiology and Prevention, M. Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
| | - Xiaolin Liang
- Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Douglas A. Levine
- Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Loic Le Marchand
- Cancer Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Laurence N. Kolonel
- Cancer Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, United States of America
| | - Brian E. Henderson
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Montserrat Garcia-Closas
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America
| | - Jennifer Anne Doherty
- Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Immaculata De Vivo
- Department of Epidemiology, Program in Molecular and Genetic Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Chu Chen
- Department of Epidemiology, School of Public Health, University of Washington, Seattle, Washington, United States of America
- Program in Epidemiology, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Otolaryngology: Head and Neck Surgery, School of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Louise A. Brinton
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, United States of America
| | - Mohammad R. Akbari
- Women's College Research Institute, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Marc T. Goodman
- Cancer Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, Hawaii, United States of America
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115
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Larder R, Cheung MKM, Tung YCL, Yeo GSH, Coll AP. Where to go with FTO? Trends Endocrinol Metab 2011; 22:53-9. [PMID: 21131211 DOI: 10.1016/j.tem.2010.11.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 11/04/2010] [Accepted: 11/04/2010] [Indexed: 10/18/2022]
Abstract
An understanding of the mechanisms underlying body-weight regulation is crucial to tackle the growing problem of obesity. Recent technological advances in the analysis of genetic variation have given novel insights into the molecular basis of common disease. In particular, genomic variants in the fat mass and obesity-associated (FTO) gene have been consistently associated with human adiposity and metabolic disorders. Studies of the product of this previously mysterious gene have formed a vanguard in the quest to turn statistical association into hard biology. In this review, we examine data from human genetic and murine studies that explore the potential role of FTO, a member of the Fe(II)- and 2-oxoglutarate-dependent oxygenase superfamily, in the regulation of energy homeostasis and metabolism.
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Affiliation(s)
- Rachel Larder
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
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116
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Abstract
Genome-wide association studies revealed that variants within FTO (fat-mass- and obesity-associated) are strongly associated with obesity susceptibility. A recent study in Nature Genetics (Church et al., 2010) demonstrates that mice overexpressing fto exhibit a dose-dependent increase in body weight, confirming a role for FTO in the development of obesity.
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Affiliation(s)
- I Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 2QQ, UK.
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117
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Church C, Moir L, McMurray F, Girard C, Banks GT, Teboul L, Wells S, Brüning JC, Nolan PM, Ashcroft FM, Cox RD. Overexpression of Fto leads to increased food intake and results in obesity. Nat Genet 2010; 42:1086-92. [PMID: 21076408 PMCID: PMC3018646 DOI: 10.1038/ng.713] [Citation(s) in RCA: 521] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Accepted: 10/19/2010] [Indexed: 12/03/2022]
Abstract
Genome-wide association studies have identified SNPs within FTO, the human fat mass and obesity-associated gene, that are strongly associated with obesity. Individuals homozygous for the at-risk rs9939609 A allele weigh, on average, ~3 kg more than individuals with the low-risk T allele. Mice that lack FTO function and/or Fto expression display increased energy expenditure and a lean phenotype. We show here that ubiquitous overexpression of Fto leads to a dose-dependent increase in body and fat mass, irrespective of whether mice are fed a standard or a high-fat diet. Our results suggest that increased body mass results primarily from increased food intake. Mice with increased Fto expression on a high-fat diet develop glucose intolerance. This study provides the first direct evidence that increased Fto expression causes obesity in mice.
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Affiliation(s)
- Chris Church
- MRC Harwell, Metabolism and Inflammation, Harwell Science and Innovation Campus, Harwell, UK
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118
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Stratigopoulos G, LeDuc CA, Cremona ML, Chung WK, Leibel RL. Cut-like homeobox 1 (CUX1) regulates expression of the fat mass and obesity-associated and retinitis pigmentosa GTPase regulator-interacting protein-1-like (RPGRIP1L) genes and coordinates leptin receptor signaling. J Biol Chem 2010; 286:2155-70. [PMID: 21037323 DOI: 10.1074/jbc.m110.188482] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The first intron of FTO contains common single nucleotide polymorphisms associated with body weight and adiposity in humans. In an effort to identify the molecular basis for this association, we discovered that FTO and RPGRIP1L (a ciliary gene located in close proximity to the transcriptional start site of FTO) are regulated by isoforms P200 and P110 of the transcription factor, CUX1. This regulation occurs via a single AATAAATA regulatory site (conserved in the mouse) within the FTO intronic region associated with adiposity in humans. Single nucleotide polymorphism rs8050136 (located in this regulatory site) affects binding affinities of P200 and P110. Promoter-probe analysis revealed that binding of P200 to this site represses FTO, whereas binding of P110 increases transcriptional activity from the FTO as well as RPGRIP1L minimal promoters. Reduced expression of Fto or Rpgrip1l affects leptin receptor isoform b trafficking and leptin signaling in N41 mouse hypothalamic or N2a neuroblastoma cells in vitro. Leptin receptor clusters in the vicinity of the cilium of arcuate hypothalamic neurons in C57BL/6J mice treated with leptin, but not in fasted mice, suggesting a potentially important role of the cilium in leptin signaling that is, in part, regulated by FTO and RPGRIP1L. Decreased Fto/Rpgrip1l expression in the arcuate hypothalamus coincides with decreased nuclear enzymatic activity of a protease (cathepsin L) that has been shown to cleave full-length CUX1 (P200) to P110. P200 disrupts (whereas P110 promotes) leptin receptor isoform b clustering in the vicinity of the cilium in vitro. Clustering of the receptor coincides with increased leptin signaling as reflected in protein levels of phosphorylated Stat3 (p-Stat3). Association of the FTO locus with adiposity in humans may reflect functional consequences of A/C alleles at rs8050136. The obesity-risk (A) allele shows reduced affinity for the FTO and RPGRIP1L transcriptional activator P110, leading to the following: 1) decreased FTO and RPGRIP1L mRNA levels; 2) reduced LEPR trafficking to the cilium; and, as a consequence, 3) a diminished cellular response to leptin.
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Affiliation(s)
- George Stratigopoulos
- Division of Molecular Genetics, Department of Pediatrics and Naomi Berrie Diabetes Center, Columbia University, New York, New York 10032, USA.
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