Gene expression profiling in developing pig adipose tissue: non-secreted regulatory proteins

Abstract

The expression of many genes encoding secreted and non-secreted factors have been studied in human and rodent adipose tissue with cDNA microarrays, but few such studies in adipose tissue from growing pigs have been reported. Total RNA was collected at slaughter from outer subcutaneous adipose tissue (OSQ) and middle subcutaneous adipose tissue (MSQ) samples from gilts at 90, 150 and 210 days (n 5 5/age). Dye-labeled cDNA probes were hybridized to custom microarrays (70-mer oligonucleotides) representing about 600 pig genes involved in growth and reproduction. Gene expression intensity ratios changed little with age for 100 transcription factors, nuclear receptors, enzymes and other regulatory proteins in OSQ and MSQ from pigs between 90 and 210 days of age. However, the relative expression of 13 genes distinguished OSQ and MSQ depots in growing pigs. The expression of several genes were influenced by age including an increase in CCND3, HSF1 and PTGR1 expression in MSQ and a decrease in UCP2 and REA (prohibitin-2) expression in OSQ. These studies demonstrate for the first time the expression of several key regulatory genes in pig adipose tissue. Simple linear regression analysis showed that leptin gene expression was associated with expression of some of these regulatory genes. Negative associations between expression of some regulatory factors and leptin gene expression indicated that local leptin may decrease or antagonize adipogenesis.

The proliferation and differentiation of primary pig preadipocytes is suppressed when cultures are incubated at 37°Celsius compared to euthermic conditions in pigs

“…This is consistent with the observation that porcine subcutaneous and intramuscular adipocytes express BMP4 mRNA and that BMP4 is secreted from porcine adipose tissue. [43][44][45] The novel observation that BMP4 mRNA was upregulated during differentiation in the present study further supports the hypothesis that BMP4 may regulate adipogenesis in the pig.…”

Preadipocyte and Adipose Tissue Differentiation in Meat Animals: Influence of Species and Anatomical Location

“…Because gene-expression profiles should reflect the different functions of the BF layers, OSQ and MSQ, mRNA were compared in pigs at three ages with custom-designed microarrays of 600 oligonucleotides representing genes involved in reproduction, growth, and adipose tissue biology (133)(134)(135). The number of genes differentially expressed with age (P < 0.001) was very dependent on the BF layer.…”

“…Twenty genes were differentially expressed between days 90 and 210 and 17 were differentially expressed between days 90 and 150 in MSQ. In contrast, 11 genes were differentially expressed between days 90 and 210 and 2 were differentially expressed between days 90 and 150 in OSQ (133)(134)(135). Furthermore, relative gene expression determined from OSQ and MSQ microarray data clearly demonstrated distinct patterns of gene expression within apolipoproteins, interleukins, interferons, and TGFb family members (133).…”

“…This reflects either the decrease in metabolic activity of adipose tissue with age or greater activity in adipose tissue of the younger pigs. These studies demonstrated differential expression of neuropeptides and neurotrophic factors in pig adipose tissue, but developmental associations or processes are yet to be discovered ( Table 3) (133)(134)(135).…”

Adipogenic Transcriptome Profiling Using High Throughput Technologies

“…Quantitative real-time PCR (qRT-PCR) combines the amplification of a DNA sequence with the detection of the amplified products during each reaction cycle and is a commonly used validation tool for confirming gene expression results obtained from microarray analysis 13. Microarray technology has been used in several gene expression profiling studies (see Table 1 for some examples) in cell culture models from mouse pre-adipocyte cell line 3T3-L1 14-18, human mesenchymal stem cells or subcutaneous abdominal fat sample 19-23, bovine 24-27, pig 28-30 as well as other organisms 31 to monitor transcriptional changes associated with adipogenesis. Different array technologies including commercially available Genome Arrays (Affymetrix), custom spotted oligonucleotide or cDNA arrays 10 have been employed in conjunction with qRT-PCR for most of these studies to identify molecular changes at different stages of adipogenesis in response to different treatments for differentiation 10, 17, 32, 33.…”