title: Blubber transcriptome response to acute stress axis activation involves transient changes in adipogenesis and lipolysis in a fasting-adapted marine mammal.
abstract: Stress can compromise an animal's ability to conserve metabolic stores and participate in energy-demanding activities that are critical for fitness. Understanding how wild animals, especially those already experiencing physiological extremes (e.g. fasting), regulate stress responses is critical for evaluating the impacts of anthropogenic disturbance on physiology and fitness, key challenges for conservation. However, studies of stress in wildlife are often limited to baseline endocrine measurements and few have investigated stress effects in fasting-adapted species. We examined downstream molecular consequences of hypothalamic-pituitary-adrenal (HPA) axis activation by exogenous adrenocorticotropic hormone (ACTH) in blubber of northern elephant seals due to the ease of blubber sampling and its key role in metabolic regulation in marine mammals. We report the first phocid blubber transcriptome produced by RNAseq, containing over 140,000 annotated transcripts, including metabolic and adipocytokine genes of interest. The acute response of blubber to stress axis activation, measured 2 hours after ACTH administration, involved highly specific, transient (lasting <24 hours) induction of gene networks that promote lipolysis and adipogenesis in mammalian adipocytes. Differentially expressed genes included key adipogenesis factors which can be used as blubber-specific markers of acute stress in marine mammals of concern for which sampling of other tissues is not possible.
authors.affiliation: Department of Biological Sciences, University of the Pacific, 3601 Pacific Avenue, Stockton, CA 95211, USA.|National Marine Mammal Foundation, 2240 Shelter Island Drive Suite 200, San Diego, CA 92106, USA.
authors.forename: J I
authors.initials: JI
authors.lastname: Khudyakov
authors.affiliation: National Marine Mammal Foundation, 2240 Shelter Island Drive Suite 200, San Diego, CA 92106, USA.|Department of Biological Sciences, Old Dominion University, 1 Monarch Way, Norfolk, VA 23529, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Champagne
authors.affiliation: Department of Biology, Sonoma State University, 1801 E Cotati Avenue, Rohnert Park, CA 94928, USA.
authors.forename: L M
authors.initials: LM
authors.lastname: Meneghetti
authors.affiliation: Department of Biology, Sonoma State University, 1801 E Cotati Avenue, Rohnert Park, CA 94928, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Crocker
mesh_terms: D050156:Adipogenesis; D000324:Adrenocorticotropic Hormone / Q000008:administration & dosage; D000818:Animals; D059001:Aquatic Organisms / Q000502:physiology*; D020869:Gene Expression Profiling; D008066:Lipolysis; D046048:Seals, Earless / Q000502:physiology*; D017423:Sequence Analysis, RNA; D013312:Stress, Physiological
chemical_list: D000324:Adrenocorticotropic Hormone