Elucidation of molecular mechanisms of physiological variations between bovine subcutaneous and visceral fat depots under different nutritional regimes

Josue Moura Romao; Weiwu Jin; Maolong He; Tim McAllister; Le Luo Guan

doi:10.1371/journal.pone.0083211

Elucidation of molecular mechanisms of physiological variations between bovine subcutaneous and visceral fat depots under different nutritional regimes

PLoS One. 2013 Dec 9;8(12):e83211. doi: 10.1371/journal.pone.0083211. eCollection 2013.

Authors

Josue Moura Romao¹, Weiwu Jin¹, Maolong He², Tim McAllister², Le Luo Guan¹

Affiliations

¹ Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
² Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada.

Abstract

Adipose tissue plays a critical role in energy homeostasis and metabolism. There is sparse understanding of the molecular regulation at the protein level of bovine adipose tissues, especially within different fat depots under different nutritional regimes. The objective of this study was to analyze the differences in protein expression between bovine subcutaneous and visceral fat depots in steers fed different diets and to identify the potential regulatory molecular mechanisms of protein expression. Subcutaneous and visceral fat tissues were collected from 16 British-continental steers (15.5 month old) fed a high-fat diet (7.1% fat, n=8) or a control diet (2.7% fat, n=8). Protein expression was profiled using label free quantification LC-MS/MS and expression of selected transcripts was evaluated using qRT-PCR. A total of 682 proteins were characterized and quantified with fat depot having more impact on protein expression, altering the level of 51.0% of the detected proteins, whereas diet affected only 5.3%. Functional analysis revealed that energy production and lipid metabolism were among the main functions associated with differentially expressed proteins between fat depots, with visceral fat being more metabolically active than subcutaneous fat as proteins associated with lipid and energy metabolism were upregulated. The expression of several proteins was significantly correlated to subcutaneous fat thickness and adipocyte size, indicating their potential as adiposity markers. A poor correlation (r=0.245) was observed between mRNA and protein levels for 9 genes, indicating that many proteins may be subjected to post-transcriptional regulation. A total of 8 miRNAs were predicted to regulate more than 20% of lipid metabolism proteins differentially expressed between fat depots, suggesting that miRNAs play a role in adipose tissue regulation. Our results show that proteomic changes support the distinct metabolic and physiological characteristics observed between subcutaneous and visceral adipose tissue depots in cattle.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cattle
Dietary Fats / pharmacology*
Energy Metabolism / drug effects*
Gene Expression Regulation / drug effects*
Intra-Abdominal Fat / metabolism*
Lipid Metabolism / drug effects*
Male
RNA, Messenger / biosynthesis
Subcutaneous Fat / metabolism*

Substances

Dietary Fats
RNA, Messenger

Grants and funding

This work was supported by Alberta Livestock Meat Agency (2010R033R) and Alberta Innovates Bio Solutions (2010F110R). J.M.R. is supported by PhD graduate student scholarship from Alberta Innovates—Technology Futures. Provision of financial support from the Canadian Triticale Biorefinery Initiative (CTBI), Feed Opportunities from the Biofuels Industries (FOBI) and Beef Cluster of Agriculture and Agri-Food Canada are also gratefully appreciated. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.