Patterns of gene expression in pig adipose tissue: transforming growth factors, interferons, interleukins, and...

Although cDNA microarray studies have indicated the expression of unique and unexpected genes and their products in human and rodent adipose tissue, cDNA microarray studies of adipose tissue from growing pigs have not been reported. Total RNA was collected at slaughter from outer s.c. adipose tissue (OSQ), middle s.c. adipose tissue (MSQ), ovary, uterus, hypothalamus, and pituitary tissue samples from gilts at 90, 150, and 210 d (n = 5/age). Dye-labeled cDNA probes were hybridized to custom microarrays (70 mer oligonucleotides) representing approximately 600 pig genes involved in growth and reproduction. Expression intensity ratios revealed little change in expression of 27 cytokines and 4 apolipoproteins with age in OSQ and MSQ from pigs at 90, 150, and 210 d of age. Distinct patterns of relative gene expression were evident within apolipoproteins, IL, interferons, and transforming growth factor beta family members in adipose tissue from growing pigs (90-, 150-, and 210-d-old pigs). Patterns of gene expression within apolipoproteins, IL, interferons, and transforming growth factor beta family members distinguished OSQ and MSQ depots in growing pigs. We also demonstrated, for the first time, the expression of several major cytokine and apolipoprotein genes in pig adipose tissue, including small inducible cytokine A5 (RANTES), IL-1B, IL-1A, IL-12A, IL-1 receptor antagonist, and apolipoproteins A1 and E with microarray and reverse transcription-PCR assays or reverse transcription-PCR assays alone. These studies demonstrate that expression of major cytokine and apolipoprotein genes in pig adipose tissue are not influenced by age in growing pigs but may be influenced by location or depot.