Pre- and postnatal hepatic gene expression profiles of two pig breeds differing in body composition: insight into pathways of metabolic regulation

Abstract

The liver plays a central role in the regulation of the metabolic status, partitioning of nutrients, and expenditure of energy. To gain insight into hepatic metabolic pathways and key transcripts affecting traits related to body composition, liver expression profiles were compared of pigs of two breeds, the obese German Landrace (DL) and the lean Pietrain (Pi). Porcine oligonucleotide microarray were hybridized with liver cRNAs obtained at peripubertal age (180 days of age) and prenatal stages (35, 63, and 91 days postconception) that represent three developmental stages of liver, i.e., period of differentiation, period of metabolic activity, and period of glycogen accumulation. In terms of the number of genes regulated between DL and Pi, the most striking distinctions were found at peripubertal age with upregulation of key genes of lipid metabolism pathways (FASN, ACSS2, ACACA) in obese DL pigs and upregulation of genes of cell growth and/or maintenance, and protein syntheses, as well as cell proliferation pathways (PPARD, POU1F1, IGF2R), in lean Pi pigs. Moreover, time course analysis of breed-dependent expression profiles revealed breed-typical temporal regulation from prenatal stages to peripubertal age of genes assigned to biological processes involving lipid pathways and cell activity, i.e., breed differences are already initiated during early prenatal development. Information about mRNA expression levels of the two breeds differing in body composition, partitioning and utilization of nutrients and energy reveals functional candidate genes for traits related to obesity and leanness.

Integrating expression profiling and whole-genome association for dissection of fat traits in a porcine model

“…Ghazalpour et al ( 21 ) found that the mapping resolution for eQTL was signifi cantly greater in the outbred population than in F2 intercrosses and showed how this precise mapping could resolve previously identifi ed loci (in F2 intercross studies), which affect many different transcript levels (known as eQTL 'hotspots), into distinct positively correlated with FA, whereas genes with negative correlation were associated with cellular development, cellular growth, and proliferation. These fi ndings were in agreement with our previous conclusion that the genetic differences between obese and lean pig breeds were associated with upregulation of lipid metabolic pathways in obese pigs and upregulation of cell growth and/or maintenance and cell proliferation pathways in lean pigs ( 30 ).…”

Detection of differentially expressed genes in the longissimus dorsi of Northeastern Indigenous and Large White pigs

“…Through its key function in lipogenesis, FASN may play a crucial role in determining the variability in weight of abdominal adipose tissue. Moreover, it has been found to be involved in lipid metabolism pathways in studies of pre-and postnatal hepatic gene expression profiles of two pig breeds differing in body composition (Ponsuksili et al, 2007). The present study found that FASN regulates fatty acid biosynthesis, lipid biosynthesis and fatty acid synthase activity.…”

Hepatic lipogenic enzyme expression in pigs is affected by selection for decreased backfat thickness at constant intramuscular fat content

“…It is known that each fat depot has a different function with regard to lipid biosynthesis or lipid storage (Mourot, Kouba, & Peiniau, 1995;O´Hea & Leveille, 1969). In pigs, lipogenesis occurs predominantly in subcutaneous fat, although the liver also has input in this process (Ponsuksili, Murani, Walz, Schwerin, & Wimmers, 2007). Furthermore, a number of hepatic biomarkers have been shown to be associated with IMF and subcutaneous fat content (Fan, Du, & Rothschild, 2010;Jiang, Li, & Yang, 2006).…”