Clavicular brown adipose tissue has a different origin from the perirenal depot that is indicative of muscle related lineage

Abstract

Multiple evidence from human studies indicates that the primary sites for brown adipose tissue in humans are the bilateral clavicular depots. In this study we aimed to identify an analogous region in the young sheep and whether it contained microRNA (MIR) specific to muscle or adipose tissue. This was compared with perirenal‐abdominal adipose tissue which represents the major fat depot in young sheep.Four triplet‐bearing mothers were entered into the study and a randomly selected triplet euthanased at 1, 7 or 28 days of age for adipose tissue sampling. Gene expression for target genes was determined by quantitative reverse transcriptase polymerase chain reaction.MIR 206 was highly abundant in skeletal muscle and was also detectable in BAT sampled from the clavicular but not perirenal depot at all sampling ages. This was despite an age related decline in UCP1 and related genes, whereas gene expression of RIP140 increased with age.Our study suggests a different cell lineage in clavicular adipose tissue compared with other BAT depots in the young sheep. Despite showing beige characteristics with increasing age, retention of some muscular origins may mean it is more response to environmental challenges aimed at promoting BAT function. The young sheep, therefore, provides a novel model for examining the developmental process of adipose transformation in early life.