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Omics Approaches in Adipose Tissue and Skeletal Muscle Addressing the Role of Extracellular Matrix in Obesity and Metabolic Dysfunction. Int J Mol Sci 2021; 22:ijms22052756. [PMID: 33803198 PMCID: PMC7963192 DOI: 10.3390/ijms22052756] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/03/2021] [Accepted: 03/05/2021] [Indexed: 12/14/2022] Open
Abstract
Extracellular matrix (ECM) remodeling plays important roles in both white adipose tissue (WAT) and the skeletal muscle (SM) metabolism. Excessive adipocyte hypertrophy causes fibrosis, inflammation, and metabolic dysfunction in adipose tissue, as well as impaired adipogenesis. Similarly, disturbed ECM remodeling in SM has metabolic consequences such as decreased insulin sensitivity. Most of described ECM molecular alterations have been associated with DNA sequence variation, alterations in gene expression patterns, and epigenetic modifications. Among others, the most important epigenetic mechanism by which cells are able to modulate their gene expression is DNA methylation. Epigenome-Wide Association Studies (EWAS) have become a powerful approach to identify DNA methylation variation associated with biological traits in humans. Likewise, Genome-Wide Association Studies (GWAS) and gene expression microarrays have allowed the study of whole-genome genetics and transcriptomics patterns in obesity and metabolic diseases. The aim of this review is to explore the molecular basis of ECM in WAT and SM remodeling in obesity and the consequences of metabolic complications. For that purpose, we reviewed scientific literature including all omics approaches reporting genetic, epigenetic, and transcriptomic (GWAS, EWAS, and RNA-seq or cDNA arrays) ECM-related alterations in WAT and SM as associated with metabolic dysfunction and obesity.
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Advances in Understanding TKS4 and TKS5: Molecular Scaffolds Regulating Cellular Processes from Podosome and Invadopodium Formation to Differentiation and Tissue Homeostasis. Int J Mol Sci 2020; 21:ijms21218117. [PMID: 33143131 PMCID: PMC7663256 DOI: 10.3390/ijms21218117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023] Open
Abstract
Scaffold proteins are typically thought of as multi-domain "bridging molecules." They serve as crucial regulators of key signaling events by simultaneously binding multiple participants involved in specific signaling pathways. In the case of epidermal growth factor (EGF)-epidermal growth factor receptor (EGFR) binding, the activated EGFR contacts cytosolic SRC tyrosine-kinase, which then becomes activated. This process leads to the phosphorylation of SRC-substrates, including the tyrosine kinase substrates (TKS) scaffold proteins. The TKS proteins serve as a platform for the recruitment of key players in EGFR signal transduction, promoting cell spreading and migration. The TKS4 and the TKS5 scaffold proteins are tyrosine kinase substrates with four or five SH3 domains, respectively. Their structural features allow them to recruit and bind a variety of signaling proteins and to anchor them to the cytoplasmic surface of the cell membrane. Until recently, TKS4 and TKS5 had been recognized for their involvement in cellular motility, reactive oxygen species-dependent processes, and embryonic development, among others. However, a number of novel functions have been discovered for these molecules in recent years. In this review, we attempt to cover the diverse nature of the TKS molecules by discussing their structure, regulation by SRC kinase, relevant signaling pathways, and interaction partners, as well as their involvement in cellular processes, including migration, invasion, differentiation, and adipose tissue and bone homeostasis. We also describe related pathologies and the established mouse models.
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Albuquerque D, González LM, Ferrer FG, Bruna M, Sánchez C, Benito GM, Rodríguez-López R, Manco L. Association study of six single nucleotide polymorphisms with obesity in two independent Iberian samples. Meta Gene 2018. [DOI: 10.1016/j.mgene.2018.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Tan LJ, Zhu H, He H, Wu KH, Li J, Chen XD, Zhang JG, Shen H, Tian Q, Krousel-Wood M, Papasian CJ, Bouchard C, Pérusse L, Deng HW. Replication of 6 obesity genes in a meta-analysis of genome-wide association studies from diverse ancestries. PLoS One 2014; 9:e96149. [PMID: 24879436 PMCID: PMC4039436 DOI: 10.1371/journal.pone.0096149] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 04/03/2014] [Indexed: 12/30/2022] Open
Abstract
Obesity is a major public health problem with a significant genetic component. Multiple DNA polymorphisms/genes have been shown to be strongly associated with obesity, typically in populations of European descent. The aim of this study was to verify the extent to which 6 confirmed obesity genes (FTO, CTNNBL1, ADRB2, LEPR, PPARG and UCP2 genes) could be replicated in 8 different samples (n = 11,161) and to explore whether the same genes contribute to obesity-susceptibility in populations of different ancestries (five Caucasian, one Chinese, one African-American and one Hispanic population). GWAS-based data sets with 1000 G imputed variants were tested for association with obesity phenotypes individually in each population, and subsequently combined in a meta-analysis. Multiple variants at the FTO locus showed significant associations with BMI, fat mass (FM) and percentage of body fat (PBF) in meta-analysis. The strongest association was detected at rs7185735 (P-value = 1.01×10(-7) for BMI, 1.80×10(-6) for FM, and 5.29×10(-4) for PBF). Variants at the CTNNBL1, LEPR and PPARG loci demonstrated nominal association with obesity phenotypes (meta-analysis P-values ranging from 1.15×10(-3) to 4.94×10(-2)). There was no evidence of association with variants at ADRB2 and UCP2 genes. When stratified by sex and ethnicity, FTO variants showed sex-specific and ethnic-specific effects on obesity traits. Thus, it is likely that FTO has an important role in the sex- and ethnic-specific risk of obesity. Our data confirmed the role of FTO, CTNNBL1, LEPR and PPARG in obesity predisposition. These findings enhanced our knowledge of genetic associations between these genes and obesity-related phenotypes, and provided further justification for pursuing functional studies of these genes in the pathophysiology of obesity. Sex and ethnic differences in genetic susceptibility across populations of diverse ancestries may contribute to a more targeted prevention and customized treatment of obesity.
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Affiliation(s)
- Li-Jun Tan
- Laboratory of Molecular and Statistical Genetics and Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
| | - Hu Zhu
- Laboratory of Molecular and Statistical Genetics and Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
| | - Hao He
- School of Public Health and Tropical Medicine and/or School of Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Ke-Hao Wu
- Laboratory of Molecular and Statistical Genetics and Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
| | - Jian Li
- School of Public Health and Tropical Medicine and/or School of Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Xiang-Ding Chen
- Laboratory of Molecular and Statistical Genetics and Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
| | - Ji-Gang Zhang
- School of Public Health and Tropical Medicine and/or School of Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Hui Shen
- School of Public Health and Tropical Medicine and/or School of Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Qing Tian
- School of Public Health and Tropical Medicine and/or School of Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Marie Krousel-Wood
- School of Public Health and Tropical Medicine and/or School of Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Christopher J. Papasian
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Claude Bouchard
- Human Genomics Laboratory, Pennington Biomedical Research Center, Baton Rouge, Louisiana, United States of America
| | - Louis Pérusse
- Department of Kinesiology, Laval University, Québec, Québec, Canada
| | - Hong-Wen Deng
- Laboratory of Molecular and Statistical Genetics and Key Laboratory of Protein Chemistry and Developmental Biology of the Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, Hunan, China
- School of Public Health and Tropical Medicine and/or School of Medicine, Tulane University, New Orleans, Louisiana, United States of America
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Fall T, Ingelsson E. Genome-wide association studies of obesity and metabolic syndrome. Mol Cell Endocrinol 2014; 382:740-757. [PMID: 22963884 DOI: 10.1016/j.mce.2012.08.018] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 05/04/2012] [Accepted: 08/27/2012] [Indexed: 11/29/2022]
Abstract
Until just a few years ago, the genetic determinants of obesity and metabolic syndrome were largely unknown, with the exception of a few forms of monogenic extreme obesity. Since genome-wide association studies (GWAS) became available, large advances have been made. The first single nucleotide polymorphism robustly associated with increased body mass index (BMI) was in 2007 mapped to a gene with for the time unknown function. This gene, now known as fat mass and obesity associated (FTO) has been repeatedly replicated in several ethnicities and is affecting obesity by regulating appetite. Since the first report from a GWAS of obesity, an increasing number of markers have been shown to be associated with BMI, other measures of obesity or fat distribution and metabolic syndrome. This systematic review of obesity GWAS will summarize genome-wide significant findings for obesity and metabolic syndrome and briefly give a few suggestions of what is to be expected in the next few years.
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Affiliation(s)
- Tove Fall
- Dept. of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Erik Ingelsson
- Dept. of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 77 Stockholm, Sweden.
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Kupca S, Sjakste T, Paramonova N, Sugoka O, Rinkuza I, Trapina I, Daugule I, Sipols AJ, Rumba-Rozenfelde I. Association of obesity with proteasomal gene polymorphisms in children. J Obes 2013; 2013:638154. [PMID: 24455213 PMCID: PMC3880696 DOI: 10.1155/2013/638154] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 10/29/2013] [Accepted: 11/22/2013] [Indexed: 11/17/2022] Open
Abstract
The aim of this study was to ascertain possible associations between childhood obesity, its anthropometric and clinical parameters, and three loci of proteasomal genes rs2277460 (PSMA6 c.-110C>A), rs1048990 (PSMA6 c.-8C>G), and rs2348071 (PSMA3 c. 543+138G>A) implicated in obesity-related diseases. Obese subjects included 94 otherwise healthy children in Latvia. Loci were genotyped and then analyzed using polymerase chain reactions, with results compared to those of 191 nonobese controls. PSMA3 SNP frequency differences between obese children and controls, while not reaching significance, suggested a trend. These differences, however, proved highly significant (P < 0.002) in the subset of children reporting a family history of obesity. Among obese children denying such history, PSMA6 c.-8C>G SNP differences, while being nonsignificant, likewise suggested a trend in comparison to the nonobese controls. No PSMA6 c.-110C>A SNP differences were detected in the obese group or its subsets. Finally, PSMA3 SNP differences were significantly associated (P < 0.05) with circulating low-density lipoprotein cholesterol (LDL) levels. Our results clearly implicate the PSMA3 gene locus as an obesity risk factor in those Latvian children with a family history of obesity. While being speculative, the clinical results are suggestive of altered circulatory LDL levels playing a possible role in the etiology of obesity in the young.
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Affiliation(s)
- Sarmite Kupca
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
- Institute of Experimental and Clinical Medicine, University of Latvia, No. 4 Ojara Vaciesa Street, Riga 1004, Latvia
| | - Tatjana Sjakste
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
| | - Natalija Paramonova
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
| | - Olga Sugoka
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
| | - Irena Rinkuza
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
| | - Ilva Trapina
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
| | - Ilva Daugule
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
| | - Alfred J. Sipols
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
- Institute of Experimental and Clinical Medicine, University of Latvia, No. 4 Ojara Vaciesa Street, Riga 1004, Latvia
- *Alfred J. Sipols:
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Lee S, Kwon MS, Park T. Network graph analysis of gene-gene interactions in genome-wide association study data. Genomics Inform 2012; 10:256-62. [PMID: 23346039 PMCID: PMC3543927 DOI: 10.5808/gi.2012.10.4.256] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 11/14/2012] [Accepted: 11/16/2012] [Indexed: 12/18/2022] Open
Abstract
Most common complex traits, such as obesity, hypertension, diabetes, and cancers, are known to be associated with multiple genes, environmental factors, and their epistasis. Recently, the development of advanced genotyping technologies has allowed us to perform genome-wide association studies (GWASs). For detecting the effects of multiple genes on complex traits, many approaches have been proposed for GWASs. Multifactor dimensionality reduction (MDR) is one of the powerful and efficient methods for detecting high-order gene-gene (GxG) interactions. However, the biological interpretation of GxG interactions identified by MDR analysis is not easy. In order to aid the interpretation of MDR results, we propose a network graph analysis to elucidate the meaning of identified GxG interactions. The proposed network graph analysis consists of three steps. The first step is for performing GxG interaction analysis using MDR analysis. The second step is to draw the network graph using the MDR result. The third step is to provide biological evidence of the identified GxG interaction using external biological databases. The proposed method was applied to Korean Association Resource (KARE) data, containing 8838 individuals with 327,632 single-nucleotide polymorphisms, in order to perform GxG interaction analysis of body mass index (BMI). Our network graph analysis successfully showed that many identified GxG interactions have known biological evidence related to BMI. We expect that our network graph analysis will be helpful to interpret the biological meaning of GxG interactions.
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Affiliation(s)
- Sungyoung Lee
- Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 151-747, Korea
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Abstract
Obesity and related complications are major health burdens. Almost 700 million adults are currently obese globally and the prevalence is predicted to rise towards 2030. The sudden change of lifestyle with physical inactivity and excessive calorie intake undoubtedly have a major part of the epidemic development; however, some individuals seem to be more prone to be affected by an unhealthy lifestyle than others. Hence, genetic predisposition also has an essential role in determining disease susceptibility and response to lifestyle factors. Since the introduction of genome-wide association studies (GWAS), the success of identifying obesity susceptibility variants have increased, and a total of 32 variants have been identified associating genome-wide significantly with body mass index (BMI) and 18 with measures of fat distribution during four overall obesity GWAS waves. However, the immediate success of the GWAS approach has eased off, but the proportion of explained variance for BMI by the identified obesity variants remains low. This review suggests and discusses new initiatives to take GWAS of obesity to the next level, including gene–environment interactions as modulating/masking factors, low-frequent or rare variants and ways to address such analyses, and finally reflections about the applicability of epigenetic modifications when elucidating the genetic background of obesity.
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Affiliation(s)
- C H Sandholt
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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Huhn S, Pardini B, Naccarati A, Vodicka P, Hemminki K, Försti A. Ancestral susceptibility to colorectal cancer. Mutagenesis 2012; 27:197-204. [PMID: 22294767 DOI: 10.1093/mutage/ger061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Every year, approximately 1 million new colorectal cancer (CRC) cases are diagnosed and about half a million people worldwide die due to this cancer. Known differences in CRC incidence rates are mainly attributed to differences in diet and other environmental factors represented, among others, by nutrition-related complex diseases (e.g. obesity and diabetes mellitus type II). Within the last years, it has become evident that environmental risk factors can be complemented by a genetic component when considering the risk of CRC. For example, a number of polymorphisms are known to be associated with an increased risk of obesity and obesity is a risk factor for CRC. Several studies have shown that the 'ancestral-susceptibility model' can be reasonably applied to nutrition-related complex diseases such as obesity. The work in hand shortly discusses whether the ancestral-susceptibility model can also be applied to CRC as a nutrition-related complex disease.
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Affiliation(s)
- Stefanie Huhn
- Department of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69121 Heidelberg, Germany
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Abstract
Obesity has reached epidemic proportions and is recognised as a significant global health problem. Increased food intake and decreased physical activity are traditionally to blame for the development of obesity; however, many variables such as behaviour, diet, environment, social structures and genetics also contribute to this multifactorial disease. Complex interactions among these variables (for example, gene-environment, gene-diet and gene-gene) contribute not only to individual differences in the development of obesity, but also in treatment response. Mouse models have historically played valuable roles in understanding the genetics of traits related to energy balance and obesity. In the present review, we survey past use and examine new advances in mouse models designed to uncover the genetic architecture of obesity and its component traits. We discuss traditional models such as inbred strains and selectively bred lines and their contributions and shortcomings. We consider the evolution of mouse models into more informative resources such as outbred crosses and the Hybrid Mouse Diversity Panel, as well as novel next-generation approaches such as the Collaborative Cross. Moreover, the genetic architecture of voluntary exercise and the interactive relationship between host genetics and the gut microbiome are presented as novel phenotypes that augment studies using body weight and body fat percentage as endpoints. Understanding the intricate network of phenotypic, genotypic and environmental variables that predispose individuals to obesity will elucidate biological networks involved in the development of obesity. Knowledge obtained from advances in mouse models will inform human health and provide insight into inter-individual variability in the aetiology of obesity-related diseases.
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Jiao H, Arner P, Hoffstedt J, Brodin D, Dubern B, Czernichow S, van't Hooft F, Axelsson T, Pedersen O, Hansen T, Sørensen TIA, Hebebrand J, Kere J, Dahlman-Wright K, Hamsten A, Clement K, Dahlman I. Genome wide association study identifies KCNMA1 contributing to human obesity. BMC Med Genomics 2011; 4:51. [PMID: 21708048 PMCID: PMC3148553 DOI: 10.1186/1755-8794-4-51] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 06/28/2011] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Recent genome-wide association (GWA) analyses have identified common single nucleotide polymorphisms (SNPs) that are associated with obesity. However, the reported genetic variation in obesity explains only a minor fraction of the total genetic variation expected to be present in the population. Thus many genetic variants controlling obesity remain to be identified. The aim of this study was to use GWA followed by multiple stepwise validations to identify additional genes associated with obesity. METHODS We performed a GWA analysis in 164 morbidly obese subjects (BMI:body mass index>40 kg/m2) and 163 Swedish subjects (>45 years) who had always been lean. The 700 SNPs displaying the strongest association with obesity in the GWA were analyzed in a second cohort comprising 460 morbidly obese subjects and 247 consistently lean Swedish adults. 23 SNPs remained significantly associated with obesity (nominal P<0.05) and were in a step-wise manner followed up in five additional cohorts from Sweden, France, and Germany together comprising 4214 obese and 5417 lean or population-based control individuals. Three samples, n=4133, were used to investigate the population-based associations with BMI. Gene expression in abdominal subcutaneous adipose tissue in relation to obesity was investigated for14 adults. RESULTS Potassium channel, calcium activated, large conductance, subfamily M, alpha member (KCNMA1) rs2116830*G and BDNF rs988712*G were associated with obesity in five of six investigated case-control cohorts. In meta-analysis of 4838 obese and 5827 control subjects we obtained genome-wide significant allelic association with obesity for KCNMA1 rs2116830*G with P=2.82×10(-10) and an odds ratio (OR) based on cases vs controls of 1.26 [95% C.I. 1.12-1.41] and for BDNF rs988712*G with P=5.2×10(-17) and an OR of 1.36 [95% C.I. 1.20-1.55]. KCNMA1 rs2116830*G was not associated with BMI in the population-based samples. Adipose tissue (P=0.0001) and fat cell (P=0.04) expression of KCNMA1 was increased in obesity. CONCLUSIONS We have identified KCNMA1 as a new susceptibility locus for obesity, and confirmed the association of the BDNF locus at the genome-wide significant level.
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Affiliation(s)
- Hong Jiao
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83 Huddinge, Sweden
- Clinical Research Centre, Karolinska University Hospital, SE-141 57 Stockholm, Sweden
| | - Peter Arner
- Department of Medicine at Karolinska Institutet and Karolinska University Hospital, SE-141 86 Stockholm, Sweden
| | - Johan Hoffstedt
- Department of Medicine at Karolinska Institutet and Karolinska University Hospital, SE-141 86 Stockholm, Sweden
| | - David Brodin
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83 Huddinge, Sweden
| | - Beatrice Dubern
- INSERM, U-557/INRA U-1125, CNAM, UP13, CRNH-IdF, 93017 Bobigny, France; University Paris 13, 93017, Bobigny, France; AP-HP, Avicenne Hospital, 93017 Bobigny, France
| | - Sébastien Czernichow
- INSERM, U-557/INRA U-1125, CNAM, UP13, CRNH-IdF, 93017 Bobigny, France; University Paris 13, 93017, Bobigny, France; AP-HP, Avicenne Hospital, 93017 Bobigny, France
| | - Ferdinand van't Hooft
- Cardiovascular Genetics Group, Atherosclerosis Research Unit, Department of Medicine Solna, Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Tomas Axelsson
- Department of Medical Sciences, Molecular Medicine, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Oluf Pedersen
- Hagedorn Research Institute, Gentofte,, Copenhagen, Denmark
- Center of Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Denmark
| | - Torben Hansen
- Hagedorn Research Institute, Gentofte,, Copenhagen, Denmark
- Center of Basic Metabolic Research, Faculty of Health Sciences, University of Copenhagen, Denmark
| | - Thorkild IA Sørensen
- Institute for Preventive Medicine, Copenhagen University Hospital, Center for Health and Society, Copenhagen, Denmark
| | - Johannes Hebebrand
- Department of Child and Adolescent Psychiatry of the University of Duisburg-Essen, Essen, Germany
| | - Juha Kere
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83 Huddinge, Sweden
- Clinical Research Centre, Karolinska University Hospital, SE-141 57 Stockholm, Sweden
| | - Karin Dahlman-Wright
- Department of Biosciences and Nutrition, Karolinska Institutet, SE-141 83 Huddinge, Sweden
| | - Anders Hamsten
- Cardiovascular Genetics Group, Atherosclerosis Research Unit, Department of Medicine Solna, Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Karine Clement
- INSERM, U-872, Nutriomique (team 7) 75006 Paris, France; University Pierre and Marie Curie-Paris 6, Cordeliers Research Center, 75006 Paris, France; AP-HP, Pitié-Salpétrière Hospital, 75013 Paris, France
| | - Ingrid Dahlman
- Department of Medicine at Karolinska Institutet and Karolinska University Hospital, SE-141 86 Stockholm, Sweden
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Abstract
The genetic contribution to interindividual variation in common obesity has been estimated at 40-70%. Yet, despite a relatively high heritability, the search for obesity susceptibility genes has been an arduous task. This paper reviews recent progress made in the obesity genetics field with an emphasis on established obesity susceptibility loci identified through candidate gene as well as genome-wide studies. For the last 15 years, candidate gene and genome-wide linkage studies have been the two main genetic epidemiological approaches to identify genetic loci for common traits, yet progress has been slow and success limited. Only recently have candidate gene studies started to succeed; by means of large-scale studies and meta-analyses at least five variants in four candidate genes have been found to be robustly associated with obesity-related traits. Genome-wide linkage studies, however, have so far not been able to pinpoint genetic loci for common obesity. The genome-wide association approach, which has become available in recent years, has dramatically changed the pace of gene discoveries for common disease, including obesity. Three waves of large-scale high-density genome-wide association studies have already discovered at least 15 previously unanticipated genetic loci incontrovertibly associated with body mass index and extreme obesity risk. Although the combined contribution of these loci to the variation in obesity risk at the population level is small and their predictive value is typically low, these recently discovered loci are set to improve fundamentally our insights into the pathophysiology of obesity.
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Affiliation(s)
- Ruth J F Loos
- MRC Epidemiology Unit, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK.
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Mao M, Thedens DR, Chang B, Harris BS, Zheng QY, Johnson KR, Donahue LR, Anderson MG. The podosomal-adaptor protein SH3PXD2B is essential for normal postnatal development. Mamm Genome 2009; 20:462-75. [PMID: 19669234 DOI: 10.1007/s00335-009-9210-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 07/10/2009] [Indexed: 01/07/2023]
Abstract
Podosome-type adhesions are actin-based membrane protrusions involved in cell-matrix adhesion and extracellular matrix degradation. Despite growing knowledge of many proteins associated with podosome-type adhesions, much remains unknown concerning the function of podosomal proteins at the level of the whole animal. In this study, the spontaneous mouse mutant nee was used to identify a component of podosome-type adhesions that is essential for normal postnatal growth and development. Mice homozygous for the nee allele exhibited runted growth, craniofacial and skeletal abnormalities, ocular anterior segment dysgenesis, and hearing impairment. Adults also exhibited infertility and a form of lipodystrophy. Using genetic mapping and DNA sequencing, the cause of nee phenotypes was identified as a 1-bp deletion within the Sh3pxd2b gene on mouse Chromosome 11. Whereas the wild-type Sh3pxd2b gene is predicted to encode a protein with one PX domain and four SH3 domains, the nee mutation is predicted to cause a frameshift and a protein truncation altering a portion of the third SH3 domain and deleting all of the fourth SH3 domain. The SH3PXD2B protein is believed to be an important component of podosomes likely to mediate protein-protein interactions with membrane-spanning metalloproteinases. Testing this directly, SH3PXD2B localized to podosomes in constitutively active Src-transfected fibroblasts and through its last SH3 domain associated with a transmembrane member of a disintegrin and metalloproteinase family of proteins, ADAM15. These results identify SH3PXD2B as a podosomal-adaptor protein required for postnatal growth and development, particularly within physiologic contexts involving extracellular matrix regulation.
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Affiliation(s)
- Mao Mao
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, IA 52242, USA
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