title: Hepatic expression patterns in psychosocially high-stressed pigs suggest mechanisms following allostatic principles.
abstract: Psychosocial challenges are known to introduce cellular and humoral adaptations in various tissues and organs, including parts of the sympatho-adrenal-medullary system and hypothalamic-pituitary-adrenal axis as well as other peripheral tissue being responsive to cortisol and catecholamines. The liver is of particular interest given its vital roles in maintaining homeostasis and health as well as regulating nutrient utilization and overall metabolism. We aimed to evaluate whether and how response to psychosocial stress is reflected by physiological molecular pathways in liver tissue. A pig mixing experiment was conducted to induce psychosocial stress culminating in skin lesions which reflect the involvement in aggressive behavior and fighting. At 27 weeks of age, animals prone to psychosocially low- and high-stress were assigned to mixing groups. Skin lesions were counted before mixing and after slaughter on the carcass. Individual liver samples (n=12) were taken. The isolated RNA was hybridized on Affymetrix GeneChip porcine Genome Arrays. Relative changes of mRNA abundances were estimated via variance analyses. Molecular routes related to tRNA charging, urea cycle, acute phase response, galactose utilization, and steroid receptor signaling were found to be increased in psychosocially high-stressed animals, whereas catecholamine degradation and cholesterol biosynthesis were found to be decreased. In particular, psychosocially high-stressed animals show decreased expression of catechol-O-methyltransferase (COMT) which has been linked to molecular mechanisms regulating aggressiveness and stress response. The expression patterns of high-stressed animals revealed metabolic alterations of key genes related to energy-mobilizing processes at the expense of energy consuming processes. Thus, the coping following psychosocial challenges involves transcriptional alterations in liver tissue which may be summarized with reference to the concept of allostasis, a strategy which is critical for survival.
authors.affiliation: Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany. Electronic address: oster@fbn-dummerstorf.de.
authors.forename: M
authors.initials: M
authors.lastname: Oster
authors.affiliation: Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany. Electronic address: murani@fbn-dummerstorf.de.
authors.forename: E
authors.initials: E
authors.lastname: Muráni
authors.affiliation: Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany. Electronic address: s.wimmers@fbn-dummerstorf.de.
authors.forename: S
authors.initials: S
authors.lastname: Ponsuksili
authors.affiliation: Animal & Veterinary Science Research Group, SRUC, West Mains Road, Edinburgh EH9 3JG, UK. Electronic address: rick.death@sruc.ac.uk.
authors.forename: R B
authors.initials: RB
authors.lastname: D'Eath
authors.affiliation: Animal & Veterinary Science Research Group, SRUC, West Mains Road, Edinburgh EH9 3JG, UK. Electronic address: Simon.Turner@sruc.ac.uk.
authors.forename: S P
authors.initials: SP
authors.lastname: Turner
authors.affiliation: PIC UK, 2 Kingston Business Park, Kingston Bagpuize, Oxfordshire OX13 5FE, UK. Electronic address: Gary.Evans@pic.com.
authors.forename: G
authors.initials: G
authors.lastname: Evans
authors.affiliation: PIC Germany, PIC Deutschland GmbH, Ratsteich 31, 24837 Schleswig, Germany. Electronic address: Ludger.Thoelking@pic.com.
authors.forename: L
authors.initials: L
authors.lastname: Thölking
authors.affiliation: Optimeter, Oyak sitesi 1.kisim 11b blok da:4, Sefakoy, Istanbul, Turkey. Electronic address: esrakurt@hotmail.com.
authors.forename: E
authors.initials: E
authors.lastname: Kurt
authors.affiliation: Vion Food Group, Boseind 10, 5281 RM Boxtel Postbus1, 5280 AA Boxtel, The Netherlands. Electronic address: ronald.klont@vionfood.com.
authors.forename: R
authors.initials: R
authors.lastname: Klont
authors.affiliation: Université Victor Segalen Bordeaux 2, PsyNuGen, UMR 1286, INRA, 33076 Bordeaux, France. Electronic address: aline.foury@bordeaux.inra.fr.
authors.forename: A
authors.initials: A
authors.lastname: Foury
authors.affiliation: Université Victor Segalen Bordeaux 2, PsyNuGen, UMR 1286, INRA, 33076 Bordeaux, France. Electronic address: pierre.mormede@toulouse.inra.fr.
authors.forename: P
authors.initials: P
authors.lastname: Mormède
authors.affiliation: Leibniz Institute for Farm Animal Biology (FBN), Institute for Genome Biology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf, Germany. Electronic address: wimmers@fbn-dummerstorf.de.
authors.forename: K
authors.initials: K
authors.lastname: Wimmers
mesh_terms: D000374:Aggression / Q000502:physiology; D052636:Allostasis / Q000502:physiology*; D000818:Animals; D002394:Catechol O-Methyltransferase / Q000096:biosynthesis* / Q000502:physiology; D005260:Female; D015870:Gene Expression / Q000502:physiology; D008099:Liver / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D060888:Real-Time Polymerase Chain Reaction; D013315:Stress, Psychological / Q000378:metabolism / Q000503:physiopathology*; D013552:Swine / Q000502:physiology
chemical_list: D002394:Catechol O-Methyltransferase
keywords: Allostasis; Liver; Microarray; Mixing; Pig; Psychosocial stress