Lele Yang,Sijia Wu,Jinchao Wei,Jiagang Deng,Xiaotao Hou,Erwei Hao,Lei Zhang,Peng Li
Glucose is a primary source of energy used in most organisms. Thus, development of reliable approaches to measure intracellular glucose uptake is an important research issue. 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy- d -glucose (2-NBDG), as a fluorescent glucose derivative, has been widely used to track intracellular glucose uptake by fluorescence imaging and measuring in mammalian cells. However, the avoid-less cross-interference of intrinsic autofluorescence background and tested fluorescent compounds limits its ability to provide trustworthy information on intracellular glucose uptake. By the extraction, separation and detection of 2-NBDG, a simple, sensitive and accurate HPLC-FLD method was established and validated for the measurement of intracellular glucose uptake in HepG2 cells. The developed method has been employed successfully to assess the glucose uptake activity of anti-diabetic drugs and fluorescent natural products. A fit-for-purpose partial validation was further performed for quantification and comparison of glucose uptake in AML12, LO2 hepatocytes, L6 myoblasts and 3T3-L1 preadipocytes.
Ya-yun Liu,Jiao-jiao You,Wei Xu,Ting Zhai,Chun-yuan Du,Yong Chen,Feng-mei Han
Objective The present work was to investigate the protective effects of the aqueous extract of Gynura procumbens (GPAE) against nonalcoholic steatohepatitis (NASH) in mice and NCTC-1469 cells. Methods C57BL/6J mice were fed with methionine and choline-deficient (MCD) diet and administered simultaneously with GPAE (500 and 1000 mg/kg/d, respectively) by gavage for six weeks. The biomarkers of NASH in serum and liver were determined. NCTC-1469 cells were pretreated with 0.25 mmol/L palmitic acid (PA) plus 0.5 mmol/L oleic acid (OA) for 24 h or treated with adenovirus expressing short-hairpin RNA against CFLAR (Ad-shCFLAR) for 24 h and then treated with GPAE (80 and 160 µg/mL, respectively) for 24 h, and the content of cellular biomarkers of NASH was detected. Results In mice treated with MCD , GPAE could decrease the levels of serum ALT , AST, the content of hepatic TG , TC and MDA , repress the activities and protein expression of CYP2E1 and CYP4A and the phosphorylation of JNK, increase the activities of HO-1, CAT and GSH-Px, up-regulate the mRNA expression of PPARα, FABP5, CPT1α, ACOX, SCD-1, mGPAT, MTTP and the protein expression of CFLAR and NRF2. In NCTC-1469 cells treated with PA and OA, GPAE could decrease the content of cellular TG and ROS , promote the uptake of 2-NBDG, up-regulate the protein expression of CFLAR and NRF2. In NCTC-1469 cells treated with Ad-sh CFLAR , GPAE up-regulated the mRNA and protein expression of CFLAR, down-regulated the phosphorylation of JNK, and increased the protein expression of NRF2 and pIRS1 . Conclusion These results indicated that the activation on CFLAR-JNK pathway might be the main anti-NASH mechanism of GPAE, which on the one hand promote the β-oxidation and efflux of fatty acids in liver, and finally reduce hepatic lipid accumulation , on the other hand increase the activities of anti-oxidant enzymes and inhibit the activities of ROS generation enzymes by activating NRF2, and therefore attenuates hepatic oxidative stress damage.