title: Molecular characterization of adipose tissue in the African elephant (Loxodonta africana).
abstract: Adipose tissue (AT) is a dynamic and flexible organ with regulatory roles in physiological functions including metabolism, reproduction and inflammation; secreted adipokines, including leptin, and fatty acids facilitate many of these roles. The African elephant (Loxodonta africana) is experiencing serious challenges to optimal reproduction in captivity. The physiological and molecular basis of this impaired fertility remains unknown. AT production of leptin is a crucial molecular link between nutritional status, adiposity and fertility in many species. We propose that leptin has a similar function in the African elephant. African elephant visceral and subcutaneous adipose tissue (AT) was obtained from both sexes and a range of ages including females with known pregnancy status. RNA was extracted and histological sections created and analyzed by microarray, PCR and immunohistochemistry respectively. Gas-chromatography was used to determine the fatty acid composition of AT. Microarray expression profiling was used to compare gene expression profiles of AT from pre-pubertal versus reproductively competent adult African elephants. This study demonstrates, for the first time, leptin mRNA and protein expression in African elephant AT. The derived protein sequence of the elephant leptin protein was exploited to determine its relationship within the class I helical cytokine superfamily, which indicates that elephant leptin is most closely related to the leptin orthologs of Oryctolagus cuniculus (European rabbit), Lepus oiostolus (woolly hare), and members of the Ochotonidae (Pika). Immunohistological analysis identified considerable leptin staining within the cytoplasm of adipocytes. Significant differences in fatty acid profiles between pregnant and non-pregnant animals were revealed, most notably a reduction in both linoleic and α linoleic acid in pregnant animals. This report forms the basis for future studies to address the effect of nutrient composition and body condition on reproduction in captive and wild elephants.
authors.affiliation: Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Emeli M
authors.initials: EM
authors.lastname: Nilsson
authors.affiliation: Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Hernan P
authors.initials: HP
authors.lastname: Fainberg
authors.affiliation: Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Siew S
authors.initials: SS
authors.lastname: Choong
authors.affiliation: Advanced Data Analysis Centre, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Giles
authors.affiliation: Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Sells
authors.affiliation: The Nottingham Arabidopsis Stock Centre, Division of Plant Sciences, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Sean
authors.initials: S
authors.lastname: May
authors.affiliation: The Elephant Research and Conservation Unit, Savé Valley Conservancy, Harare, Zimbabwe.
authors.forename: Fiona J
authors.initials: FJ
authors.lastname: Stansfield
authors.affiliation: The Paul Mellon Laboratory, "Brunswick," Woodditton Road, Newmarket, Suffolk, United Kingdom.
authors.forename: William R
authors.initials: WR
authors.lastname: Allen
authors.affiliation: Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom; Advanced Data Analysis Centre, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Emes
authors.affiliation: Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Alison
authors.initials: A
authors.lastname: Mostyn
authors.affiliation: Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Nigel P
authors.initials: NP
authors.lastname: Mongan
authors.affiliation: Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham, Sutton Bonington, United Kingdom.
authors.forename: Lisa
authors.initials: L
authors.lastname: Yon
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D016000:Cluster Analysis; D004606:Elephants / Q000502:physiology*; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D020738:Leptin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000378:metabolism; D010802:Phylogeny; D011487:Protein Conformation
chemical_list: D020738:Leptin; D010743:Phospholipids