PO-119 Adrenergic Receptor β3 Up-regulates Uncoupling Protein 1 and Cyclooxygenase 2 Expressions in The Brown Adipocyte

Objective Brown adipose tissues (BAT) activation is important for losing weight as its high energy expenditure in Mammalian. Recent studies showed that exercise may also be essential for BAT activation. Uncoupling protein 1 (UCP1), specifically expressed in BAT's mitochondria, uncouples oxidative phosphorylation and dissipates energy from Free Fatty Acids into heat. Activating the Adrenergic Receptor β3 (Adrβ3) provides fuel for mitochondrial heat production and up-regulates Cyclooxygenase 2 (COX2), which is a key factor of UCP1 synthesis. Sympathetic nerve excitement stimulated by exercise can release norepinephrine as a neurotransmitter, which can affect Adrβ3. Brown adipocyte (BAC) is a kind of adipocyte in vitro as a model to study heat production. Isoprenaline Hydrochloride (ISO) is a widely used as an Adrβ agonist. In this research, we tried to figure out the response of BAC to Adrβ3 activations with different time points and whether ISO can be used as a BAC activator. Methods C3H10T1/2 cells were maintained in a humidified, 37°C, 5% CO2 incubator in DMEM/F12 medium with 10% fetal bovine serum (FBS). For brown adipogenesis, cells were first split into differentiation medium (DMEM/F12 containing 10% FBS, 20nM insulin, 1nM 3,3’5-Triiodo-L-thyronine(T3)) for 4 days, the medium was changed every other day. Confluent cells were treated for 2 days with brown adipose adipogenesis cocktails (differentiation medium containing 2µg/mL dexamethasone, 0.5mM isobutylmethylxanthine (IBMX), 0.125mM indomethacin and 1µM rosiglitazone) on day 4. Then the medium was replaced by differentiation medium and changed every other day. At day 10, the full differentiation adipocytes were treated with 10µM ISO for 0 (as control), 1, 3, 6, 12 and 24 hours. For the lipid droplets staining, the cells were fixed by 4% paraformaldehyde solution then stained with Oil Red O. The cells were harvested and the total cell lysates were extracted for protein analysis after each time point. The UCP1, COX2, and Adrβ3 expression levels were detected ...