Retinoic acids alter alpha-2-macroglobulin and ceruloplasmin bovine intramuscular adipogenesis

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 649-677-Adipocyte Biology
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-665
Daiki Taniguchi*, Akira Hasegawa, Toshio Harigaya and Yasushi Mizoguchi
Meiji University, Kawasaki Kanagawa, Japan
Adipocytes play important roles in energy homeostasis and secretion of homeostatis factors. Retinoic acids (RAs) are known regulators of adipose tissue growth. In mice, RAs are recognized as inhibitors of obesity and insulin resistance. RAs are mediated by RA receptors (RAR) and retinoid X receptors (RXR). RAR is activated by all-trans RA (ATRA), and 9-cis RA (9RA) is a high-affinity ligand for RXR. However, the molecular mechanisms of RAs during adipogenesis are largely unknown. In this study, we used bovine intramuscular preadipocytes as a adipogenesis model and investigated the effects of RAs in vitro on gene expression during adipogenesis.

 Differential gene expression levels were validated by microarray analysis in a clonal bovine intramuscular preadipocyte (BIP) cell line, which was derived from the intramuscular adipose tissue of the musculus longissimus thoraicis of Japanese Black cattle. The BIP cells were harvested six days after adipogenic stimulation with 1μM ATRA or 1μM 9RA (and controls with no RA). From the microarray analysis we found 1408 genes with over 5-fold differences in expression during BIP adipogenesis between the ATRA and 9RA treatments and the control. We also identified some genes with over 50-fold change of expression. We then conducted more detailed studies on two of the genes with the most dramatically altered expressions after differentiation,  alpha-2-macroglobulin (A2M) and ceruloplasmin (CP) genes.

 We profiled the A2M and CP gene expressions by real-time PCR during adipogenesis in BIP cells in a stimulation medium containing either 1μM ATRA or no treatment. We harvested the BIP cells 0, 3, 6, 9 and 12 days after the onset of adipogenic stimulation. In the non-treatment, the A2M gene showed up-regulation from day 0 to day 12 (222.6-fold, p<0.05). Moreover, treatment with ATRA greatly increased gene expression. Compared with non-treatment, the presence of ATRA up-regulated the expression of A2M from day 3 (36.3-fold, p<0.01) to day12 (62.9-fold, p<0.05) and up-regulated the expression of CP on day 3 and day 6 (1815.4-fold, 704.8-fold, respectively, p<0.05). Therefore, the up-regulation of A2M and CP genes by ATRA may be related to bovine adipogenesis.

Nothing to Disclose: DT, AH, TH, YM

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