Fig. 5

Role of PPARγ phosphorylation at Ser273 in DHA- or EPA-induced increases in adiponectin. a time-dependent effects of DHA and EPA (100 μmol/L) on phosphorylation of PPARγ at Ser 273. b time-dependent effect of TNF-α (20 ng/mL) or roscovitine (10 μmol/L) on phosphorylation of PPARγ at Ser 273. 3T3-L1 adipocytes were pretreated with 100 μmol/L of DHA or EPA for 24 h, followed by being respectively co-incubated with TNF-α or roscovitine for another 2 h. Besides, adipocytes were also incubated with DHA (24 h), EPA (24 h), TNF-α (2 h) or roscovitine (2 h) alone. BSA treatment served as the control. Cellular phosphorylation of PPARγ at Ser 273 (c, d) was assessed using co-immunoprecipitation assay and normalized to the control with PPARγ worked as the reference. Cellular adiponectin (c, e, f) and secreted adiponectin (g) were also quantified. Cellular adiponectin in treatment groups were normalized to the control with β-actin worked as the internal reference. Data were presented as mean ± SD, n = 5. ^a P < 0.05 versus control; ^b P < 0.05 versus EPA; ^c P < 0.05 versus TNF-α; ^* P < 0.05 DHA versus DHA + TNF-α and EPA versus EHA + roscovitine. One-way ANOVA followed by Student-Newman-Keuls (SNK) test. Co-IP: co-immunoprecipitation; Con: control; Ros: roscovitine