Kopp Christina, Singh Shiva P, Regenhard Petra, Müller Ute, Sauerwein Helga, Mielenz Manfred
Institute of Animal Science, Physiology & Hygiene Unit, University of Bonn, Katzenburgweg 7-9, Bonn 53115, Germany.
Int J Mol Sci. 2014 Feb 19;15(2):2906-15. doi: 10.3390/ijms15022906.
Adiponectin and intracellular 5'adenosine monophosphate-activated protein kinase (AMPK) are important modulators of glucose and fat metabolism. Cinnamon exerts beneficial effects by improving insulin sensitivity and blood lipids, e.g., through increasing adiponectin concentrations and AMPK activation. The underlying mechanism is unknown. The Gi/Go-protein-coupled receptor (GPR) 109A stimulates adiponectin secretion after binding its ligand niacin. Trans-cinnamic acid (tCA), a compound of cinnamon is another ligand. We hypothesize whether AMPK activation and adiponectin secretion by tCA is transmitted by GPR signaling. Differentiated 3T3-L1 cells were incubated with pertussis toxin (PTX), an inhibitor of G(i)/G(o)-protein-coupling, and treated with different tCA concentrations. Treatment with tCA increased adiponectin and the pAMPK/AMPK ratio (p ≤ 0.001). PTX incubation abolished the increased pAMPK/AMPK ratio and adiponectin secretion. The latter remained increased compared to controls (p ≤ 0.002). tCA treatment stimulated adiponectin secretion and AMPK activation; the inhibitory effect of PTX suggests GPR is involved in tCA stimulated signaling.
脂联素和细胞内5'-腺苷单磷酸激活蛋白激酶(AMPK)是葡萄糖和脂肪代谢的重要调节因子。肉桂通过改善胰岛素敏感性和血脂发挥有益作用,例如,通过增加脂联素浓度和激活AMPK。其潜在机制尚不清楚。G蛋白偶联受体(GPR)109A在结合其配体烟酸后刺激脂联素分泌。反式肉桂酸(tCA)是肉桂的一种化合物,也是另一种配体。我们推测tCA激活AMPK和分泌脂联素是否通过GPR信号传导。将分化的3T3-L1细胞与百日咳毒素(PTX,一种G(i)/G(o)蛋白偶联抑制剂)孵育,并用不同浓度的tCA处理。用tCA处理可增加脂联素和pAMPK/AMPK比值(p≤0.001)。PTX孵育消除了增加的pAMPK/AMPK比值和脂联素分泌。与对照组相比,后者仍有所增加(p≤0.002)。tCA处理刺激了脂联素分泌和AMPK激活;PTX的抑制作用表明GPR参与了tCA刺激的信号传导。