The muscular, hepatic and adipose tissues proteomes in muskox (Ovibos moschatus): Differences between males and females.

The muskox (Ovibos moschatus) is a ruminant highly adapted to arctic conditions. The objective of this work is to study liver, muscle and adipose tissues proteomes in muskoxen highlighting sex differences. Ten animals (5 per sex) were sampled in Western Greenland during the winter hunting season. During carcass processing, muscle, liver and rump fat samples were obtained. Proteomic analyses were conducted using both gel-based and gel-free approaches. Gel-free data are available (ProteomeXchange; PXD014147). For gel-free analysis, 729, 853 and 792 proteins were identified for fat, liver and muscle, respectively. Several proteins were detected with differential abundance between male and female tissues: 77, 15 and 12 proteins using gel-free for adipose tissue, liver and muscle respectively while 3 differential proteins were identified in the gel-based analysis of the adipose tissue. Females have higher abundance of proteins involved in tissue structural stability in the muscle, while males have higher abundance of proteins related to muscle development. In the liver and adipose tissue, females have higher abundance of proteins related to oxidative-stress resistance. Proteins accumulated in the adipose tissue of males highlight higher adipogenic potential. Sex dimorphism is inherent to this species, with higher abundance of proteins in specific metabolic pathways. SIGNIFICANCE: The proteomes of the muskox muscle, hepatic and adipose tissues are characterized for the first time. In addition, the effect of sex on tissue protein abundance is studied. Our results reveal that sex dimorphism goes from morphology to the molecular level in this species, affecting protein, lipid and carbohydrate metabolism. This contributes for an in-depth look into sex dimorphism using proteomics which is lacking in most mammals, apart from model species. Moreover, this information has been related to nutritional status, which is particularly important when managing the muskox population and the transformation of its habitat in relation to external factors such as climate changes that can severely affect ecosystems.