Chengjun Ma1, Gang Li2, Yanfeng He3, Bo Xu4, Xiangquan Mi5, Honglun Wang3, Zhenhua Wang6. 1. Center of Mitochondria and Healthy Aging, School of Life Sciences, Yantai University, Yantai 264005, China. 2. Center of Mitochondria and Healthy Aging, School of Life Sciences, Yantai University, Yantai 264005, China; Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xi'ning 810001, China. 3. Key Laboratory of Tibetan Medicine Research, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xi'ning 810001, China. 4. Center of Mitochondria and Healthy Aging, School of Life Sciences, Yantai University, Yantai 264005, China; Key Laboratory of Molecular Pharmacology and Drug Evaluation (Ministry of Education of China), School of Pharmacy, Yantai University, Yantai 264005, China. 5. School of Life Sciences, Lanzhou University, Lanzhou 730000, China. 6. Center of Mitochondria and Healthy Aging, School of Life Sciences, Yantai University, Yantai 264005, China. Electronic address: skywzh@ytu.edu.cn.
Abstract
AIMS: Nelumbo nucifera (Gaertn.) leaves are used widely in modulating obesity in traditional Chinese medicine. Our previous work demonstrated that aporphine alkaloids from it increased the glucose consumption in mature 3T3-L1 adipocytes. However, the underlying mechanisms of this increase remain unclear. Here we investigated the modulating effects of pronuciferine and nuciferine on lipogenesis and glucose uptake in insulin resistant 3T3-L1 adipocytes in vitro. MAIN METHODS: Insulin resistant 3T3-L1 mature adipocytes were induced with dexamethasone, 3-isobutyl-methylxanthine and insulin. The lipid droplets and the intracellular triglyceride contents in mature adipocytes were detected by Oil red O staining and colorimetry respectively. The glucose uptake was measured with a fluorescent deoxyglucose analog (2-NBDG). The glucose transporter type 4 (GLUT-4) expression was measured by fluorescent-immunohistochemistry and the activation of 5'-AMP-activated protein kinase (AMPK) was detected by its alpha subunit phosphorylation. KEY FINDINGS: Both nuciferine and pronuciferine treatments significantly decreased the lipid droplets and the intracellular triglyceride contents but increased the glucose uptake in the insulin resistant 3T3-L1 adipocytes. Furthermore, both pronuciferine and nuciferine showed the ability to up-regulate the expression of GLUT4, triggering the phosphorylation of AMPK in mature 3T3-L1 adipocytes, although pronuciferine exhibited a more powerful effect compared to nuciferine. SIGNIFICANCE: In summary, all the results demonstrate that pronuciferine and nuciferine ameliorate the glucose and lipid metabolism in insulin-resistant 3T3-L1 adipocytes, which might be due to the activation of the AMPK signaling pathway.
AIMS: Nelumbo nucifera (Gaertn.) leaves are used widely in modulating obesity in traditional Chinese medicine. Our previous work demonstrated that aporphine alkaloids from it increased the glucose consumption in mature 3T3-L1 adipocytes. However, the underlying mechanisms of this increase remain unclear. Here we investigated the modulating effects of pronuciferine and nuciferine on lipogenesis and glucose uptake in insulin resistant 3T3-L1 adipocytes in vitro. MAIN METHODS: Insulin resistant 3T3-L1 mature adipocytes were induced with dexamethasone, 3-isobutyl-methylxanthine and insulin. The lipid droplets and the intracellular triglyceride contents in mature adipocytes were detected by Oil red O staining and colorimetry respectively. The glucose uptake was measured with a fluorescent deoxyglucose analog (2-NBDG). The glucose transporter type 4 (GLUT-4) expression was measured by fluorescent-immunohistochemistry and the activation of 5'-AMP-activated protein kinase (AMPK) was detected by its alpha subunit phosphorylation. KEY FINDINGS: Both nuciferine and pronuciferine treatments significantly decreased the lipid droplets and the intracellular triglyceride contents but increased the glucose uptake in the insulin resistant 3T3-L1 adipocytes. Furthermore, both pronuciferine and nuciferine showed the ability to up-regulate the expression of GLUT4, triggering the phosphorylation of AMPK in mature 3T3-L1 adipocytes, although pronuciferine exhibited a more powerful effect compared to nuciferine. SIGNIFICANCE: In summary, all the results demonstrate that pronuciferine and nuciferine ameliorate the glucose and lipid metabolism in insulin-resistant 3T3-L1 adipocytes, which might be due to the activation of the AMPK signaling pathway.