title: RNA-Seq Analysis of Abdominal Fat in Genetically Fat and Lean Chickens Highlights a Divergence in Expression of Genes Controlling Adiposity, Hemostasis, and Lipid Metabolism.
abstract: Genetic selection for enhanced growth rate in meat-type chickens (Gallus domesticus) is usually accompanied by excessive adiposity, which has negative impacts on both feed efficiency and carcass quality. Enhanced visceral fatness and several unique features of avian metabolism (i.e., fasting hyperglycemia and insulin insensitivity) mimic overt symptoms of obesity and related metabolic disorders in humans. Elucidation of the genetic and endocrine factors that contribute to excessive visceral fatness in chickens could also advance our understanding of human metabolic diseases. Here, RNA sequencing was used to examine differential gene expression in abdominal fat of genetically fat and lean chickens, which exhibit a 2.8-fold divergence in visceral fatness at 7 wk. Ingenuity Pathway Analysis revealed that many of 1687 differentially expressed genes are associated with hemostasis, endocrine function and metabolic syndrome in mammals. Among the highest expressed genes in abdominal fat, across both genotypes, were 25 differentially expressed genes associated with de novo synthesis and metabolism of lipids. Over-expression of numerous adipogenic and lipogenic genes in the FL chickens suggests that in situ lipogenesis in chickens could make a more substantial contribution to expansion of visceral fat mass than previously recognized. Distinguishing features of the abdominal fat transcriptome in lean chickens were high abundance of multiple hemostatic and vasoactive factors, transporters, and ectopic expression of several hormones/receptors, which could control local vasomotor tone and proteolytic processing of adipokines, hemostatic factors and novel endocrine factors. Over-expression of several thrombogenic genes in abdominal fat of lean chickens is quite opposite to the pro-thrombotic state found in obese humans. Clearly, divergent genetic selection for an extreme (2.5-2.8-fold) difference in visceral fatness provokes a number of novel regulatory responses that govern growth and metabolism of visceral fat in this unique avian model of juvenile-onset obesity and glucose-insulin imbalance.
authors.affiliation: Department of Animal and Food Sciences, University of Delaware, Newark, Delaware, United States of America.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Resnyk
authors.affiliation: Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, United States of America.
authors.forename: Chuming
authors.initials: C
authors.lastname: Chen
authors.affiliation: Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, United States of America.
authors.forename: Hongzhan
authors.initials: H
authors.lastname: Huang
authors.affiliation: Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware, United States of America.
authors.forename: Cathy H
authors.initials: CH
authors.lastname: Wu
authors.affiliation: INRA UR83 Recherches Avicoles, 37380, Nouzilly, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Simon
authors.affiliation: INRA UR83 Recherches Avicoles, 37380, Nouzilly, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Le Bihan-Duval
authors.affiliation: INRA UR83 Recherches Avicoles, 37380, Nouzilly, France.
authors.forename: Michel J
authors.initials: MJ
authors.lastname: Duclos
authors.affiliation: Department of Animal and Food Sciences, University of Delaware, Newark, Delaware, United States of America.
authors.forename: Larry A
authors.initials: LA
authors.lastname: Cogburn
mesh_terms: D050153:Abdominal Fat / Q000378:metabolism*; D054392:Adipokines / Q000235:genetics; D000273:Adipose Tissue / Q000378:metabolism; D050154:Adiposity / Q000235:genetics*; D000818:Animals; D002645:Chickens / Q000235:genetics*; D005215:Fasting / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics; D020869:Gene Expression Profiling / Q000379:methods; D005838:Genotype; D006487:Hemostasis / Q000235:genetics*; D050152:Intra-Abdominal Fat / Q000378:metabolism; D050356:Lipid Metabolism / Q000235:genetics*; D050155:Lipogenesis / Q000235:genetics; D009765:Obesity / Q000235:genetics*; D012313:RNA / Q000235:genetics; D017423:Sequence Analysis, RNA / Q000379:methods; D013851:Thinness / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics
chemical_list: D054392:Adipokines; D012313:RNA