Distinct Patterns of PPARγ Promoter Usage, Lipid Degradation Activity, and Gene Expression in Subcutaneous Adipose Tissue of Lean and Obese Swine.

Guizhi Tong,Jun Liu,Ying Gao,Liyan Ding,Bin Song,Hongbao Wang,Na Chen,Shiquan Cui,Xuankai Huang,Shengwei Di,Qian Gao,Huan Wang,Xuan Wang,Xibiao Wang

doi:10.3390/ijms19123892

Abstract

Subcutaneous adipose tissue is a loose connective tissue specializing in the regulation of energy storage and metabolization. In domesticated pigs (Sus scrofa), the temporal development of subcutaneous adipose tissue is critical for meat production. However, the regulation of adipose tissue development remains unclear. Here, the subcutaneous adipose tissue development was characterized and compared in lean (Danish-Landrace) and obese (Min) pigs at juvenile and the juvenile-to-adult growth stages. Using RNA sequencing, we profiled the transcriptome of subcutaneous adipose tissue isolated from 4- and 16-week-old pigs and identified 24,718 expressed transcription units. Of them, 6327 genes were differentially expressed between the breeds and/or developmental stages. Compared with obese pigs, upregulated genes in lean pigs showed significant function and pathway enrichment in fatty acid degradation and mitochondrial functions. Further analysis uncovered the distinct usage preferences of the three alternative peroxisome proliferator-activated receptor γ (PPARγ) promoters associated with the development of subcutaneous adipose tissue in both breeds. Transcriptome analysis of subcutaneous adipose tissue in lean and obese pigs suggested that marker-assisted selection of fatty acid degradation and PPARγ signaling pathways could be important directions for future pork quality improvement and modern breeding.

Highlights

Pig (Sus scrofa, 2n = 38) is an important domesticated animal for meat production
Phylogenetic studies based on whole-genome sequences have indicated that the domestication of pigs originated in multiple locations across Southeast Asia around 3 to 4 million years ago [1,2,3,4]
Genes associated with fatty acid degradation pathways were found to be systemically upregulated in DL versus Min pigs, including acyl-CoA dehydrogenase, C-4 to C-12 straight chain, HADHA, HADH, acetyl-CoA acyltransferase-2, hydroxysteroid dehydrogenase 17-β 4, 2-hydroxyacyl-CoA lyase 1, enoyl-CoA δ isomerase-1, ATP-binding cassette subfamily D member 2, electron transfer flavoprotein subunit α, peroxisome biogenesis factor 13, and electron transfer flavoprotein dehydrogenase. These results indicate that fatty acid degradation capability is an important factor distinguishing lean and obese pig breeds

Summary

Introduction

According to the World Watch List of Domestic Animal Diversity, there are 118 indigenous pig breeds in China [5]. Similar to muscle and intramuscular fat, subcutaneous fat is one of the important factors determining the deliciousness of pork meat. The indigenous Min pig is a well-known obese breed in northeast China due to its high body fat percentage and strong resistance to cold and general diseases [12,13]. These lean and obese pig breeds serve as ideal models for studying the diversity of fat deposition between European commercial and Chinese indigenous pigs

Methods

Results

Conclusion