부산대학교 도서관

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1440-1681.2006.04348.x Byline: Ho Jae Han (*), Jung Sun Heo (*), Yun Jung Lee (*), Jung Jun Min ([dagger]), Kwang Sung Park ([dagger]) Keywords: cAMP; 2-deoxyglucose uptake; embryonic stem cell; mitogen-activated protein kinase; oxidative stress; phospholipase C; protein kinase C Abstract: SUMMARY Abnormally high glucose levels may play an important role in early embryo development and function. In the present study, we investigated the effect of high glucose on 2-deoxyglucose (2-DG) uptake and its related signalling pathway in mouse embryonic stem (ES) cells. 2-Deoxyglucose uptake was maximally inhibited by 25 mmol/L glucose after 24 h treatment. However, 25 mmol/L mannitol and dextran did not affect 2-DG uptake. Indeed, 25 mmol/L glucose decreased GLUT-1 mRNA and protein levels. The glucose (25 mmol/L)-induced inhibition of 2-DG uptake was blocked by pertussis toxin (a G.sub.i-protein inhibitor; 2 ng/mL), SQ 22536 (an adenylate cyclase inhibitor; 10.sup.-6 mol/L) and the protein kinase (PK) A inhibitor myristoylated PKI amide-(14-22) (10.sup.-6 mol/L). Indeed, 25 mmol/L glucose increased intracellular cAMP content. Furthermore, 25 mmol/L glucose-induced inhibition of 2-DG uptake was prevented by 10.sup.-4 mol/L neomycin or 10.sup.-6 mol/L U 73122 (phospholipase C (PLC) inhibitors) and staurosporine or bisindolylmaleimide I (protein kinase (PK) C inhibitors). At 25 mmol/L, glucose increased translocation of PKC from the cytoplasmic fraction to the membrane fraction. The 25 mmol/L glucose-induced inhibition of 2-DG uptake and GLUT-1 protein levels was blocked by SQ 22536, bisindolylmaleimide I or combined treatment. In addition, 25 mmol/L glucose increased cellular reactive oxygen species and the glucose-induced inhibition of 2-DG uptake were blocked by the anti-oxidants N-acetylcysteine (NAC; 10.sup.-5 mol/L) or taurine (2 [yen] 10.sup.-3 mol/L). Glucose (25 mmol/L) activated p38 mitogen-activated protein kinase (MAPK) and p44/42 MAPK. Staurosporine (10.sup.-6 mol/L), NAC (10.sup.-5 mol/L) and PD 98059 (10.sup.-7 mol/L) attenuated the phosphorylation of p44/42 MAPK. Both SB 203580 (a p38 MAPK inhibitor; 10.sup.-7 mol/L) and PD 98059 (a p44/42 MAPK inhibitor; 10.sup.-7 mol/L) blocked 25 mmol/L glucose-induced inhibition of 2-DG uptake. In conclusion, high glucose inhibits 2-DG uptake through cAMP, PLC/PKC, oxidative stress or MAPK in mouse ES cells. Author Affiliation: (*)Department of Veterinary Physiology, College of Veterinary Medicine and ([dagger])College of Medicine, Chonnam National University, Gwangju, Korea Article History: Received 8 March 2005; revision 17 October 2005; accepted 19 October 2005. Article note: Correspondence: Ho Jae Han, Department of Veterinary Physiology, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, Korea. Email: hjhan@chonnam.ac.kr