Avian Expression Patterns and Genomic Mapping Implicate Leptin in Digestion and TNF Signaling, Suggesting that Their Interacting Adipokine Role is Unique to Mammals

Eyal Seroussi (1) , Martin Knytl (2, 3) , Frederique Pitel (4) , Daniel Elleder (5) , Vladimir Krylov (2) , Sophie Leroux (4) , Mireille Morisson (4) , Sara Yosefi (1) , Shoval Miyara (1) , Saibaba Ganesan (1) , Mark Ruzal (1) , Leif Andersson (6, 7, 8) , Miriam Friedman-Einat (1)

1 Department of Animal Science, Agricultural Research Organization Volcani Center
2 Department of Developmental Biology, Faculty of Science
3 Department of Biology, Faculty of Science
4 GenPhySE - Génétique Physiologie et Systèmes d'Elevage
5 IMG / CAS - Institute of Molecular Genetics of the Czech Academy of Sciences
6 Department of Medical Biochemistry and Microbiology
7 Department of Animal Breeding and Genetics
8 Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M

In mammals, leptin and tumor-necrosis factor (TNF) are prominent interacting adipokines mediating appetite control and insulin sensitivity. While TNF pleiotropically functions in immune defense and cell survival, leptin is largely confined to signaling energy stores in adipocytes. Knowledge about the function of avian leptin and TNF is limited and they are absent or lowly expressed in adipose, respectively. Employing radiation-hybrid mapping and FISH-TSA, we mapped TNF and its syntenic genes to chicken chromosome 16 within the major histocompatibility complex (MHC) region. This mapping position suggests that avian TNF has a role in regulating immune response. To test its possible interaction with leptin within the immune system and beyond, we compared the transcription patterns of TNF, leptin and their cognate receptors obtained by meta-analysis of GenBank RNA-seq data. While expression of leptin and its receptor (LEPR) were detected in the brain and digestive tract, TNF and its receptor mRNAs were primarily found in viral-infected and LPS-treated leukocytes. We confirmed leptin expression in the duodenum by immunohistochemistry staining. Altogether, we suggest that whereas leptin and TNF interact as adipokines in mammals, in birds, they have distinct roles. Thus, the interaction between leptin and TNF may be unique to mammals.

Mots clés: radiation-hybrid mapping; FISH-TSA; TNF; chicken; digestive tract; duodenum; immune system; leptin

Domaines: Autre [q-bio.OT]

Eyal Seroussi, Martin Knytl, Frederique Pitel, Daniel Elleder, Vladimir Krylov, et al.. Avian Expression Patterns and Genomic Mapping Implicate Leptin in Digestion and TNF Signaling, Suggesting that Their Interacting Adipokine Role is Unique to Mammals. International Journal of Molecular Sciences, 2019, 20 (18), pp.1.15. ⟨10.3390/ijms20184489⟩. ⟨hal-02292491⟩