Genetical Genomics of Tonic Immobility in the Chicken
GENES
Authors: Fogelholm, Jesper; Inkabi, Samuel; Hoglund, Andrey; Abbey-Lee, Robin; Johnsson, Martin; Jensen, Per; Henriksen, Rie; Wright, Dominic
Abstract
Identifying the molecular mechanisms of animal behaviour is an enduring goal for researchers. Gaining insight into these mechanisms enables us to gain a greater understanding of behaviour and their genetic control. In this paper, we perform Quantitative Trait Loci (QTL) mapping of tonic immobility behaviour in an advanced intercross line between wild and domestic chickens. Genes located within the QTL interval were further investigated using global expression QTL (eQTL) mapping from hypothalamus tissue, as well as causality analysis. This identified five candidate genes, with the genes PRDX4 and ACOT9 emerging as the best supported candidates. In addition, we also investigated the connection between tonic immobility, meat pH and struggling behaviour, as the two candidate genes PRDX4 and ACOT9 have previously been implicated in controlling muscle pH at slaughter. We did not find any phenotypic correlations between tonic immobility, struggling behaviour and muscle pH in a smaller additional cohort, despite these behaviours being repeatable within-test.
Acyl-Coenzyme A Thioesterase 9 Traffics Mitochondrial Short-Chain Fatty Acids TowardDe NovoLipogenesis and Glucose Production in the Liver
HEPATOLOGY
Authors: Steensels, Sandra; Qiao, Jixuan; Zhang, Yanzhen; Maner-Smith, Kristal M.; Kika, Nourhan; Holman, Corey D.; Corey, Kathleen E.; Bracken, W. Clay; Ortlund, Eric A.; Ersoy, Baran A.
Abstract
Background and Aims Obesity-induced pathogenesis of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) is associated with increasedde novolipogenesis (DNL) and hepatic glucose production (HGP) that is due to excess fatty acids. Acyl-coenzyme A (CoA) thioesterase (Acot) family members control the cellular utilization of fatty acids by hydrolyzing (deactivating) acyl-CoA into nonesterified fatty acids and CoASH. Approach and Results UsingCaenorhabditis elegans, we identified Acot9 as the strongest regulator of lipid accumulation within the Acot family. Indicative of a maladaptive function, hepatic Acot9 expression was higher in patients with obesity who had NAFLD and NASH compared with healthy controls with obesity. In the setting of excessive nutrition, global ablation of Acot9 protected mice against increases in weight gain, HGP, steatosis, and steatohepatitis. Supportive of a hepatic function, the liver-specific deletion of Acot9 inhibited HGP and steatosis in mice without affecting diet-induced weight gain. By contrast, the rescue of Acot9 expression only in the livers of Acot9 knockout mice was sufficient to promote HGP and steatosis. Mechanistically, hepatic Acot9 localized to the inner mitochondrial membrane, where it deactivated short-chain but not long-chain fatty acyl-CoA. This unique localization and activity of Acot9 directed acetyl-CoA away from protein lysine acetylation and toward the citric acid (TCA) cycle. Acot9-mediated exacerbation of triglyceride and glucose biosynthesis was attributable at least in part to increased TCA cycle activity, which provided substrates for HGP and DNL. beta-oxidation and ketone body production, which depend on long-chain fatty acyl-CoA, were not regulated by Acot9. Conclusions Taken together, our findings indicate that Acot9 channels hepatic acyl-CoAs toward increased HGP and DNL under the pathophysiology of obesity. Therefore, Acot9 represents a target for the management of NAFLD.