Submitted on December 31, 2007
Accepted on June 2, 2008
FR167653 Inhibits Fibronectin Expression and Apoptosis in Diabetic Glomeruli and in High Glucose-Stimulated Mesangial Cells
Dong-Sub Jung1, Jin-Ji Li2, Seung-Jae Kwak1, Sun Ha Lee1, Jehyun Park1, Young Soo Song3, Tae-Hyun Yoo1, Seung Hyeok Han1, Jung Eun Lee1, Dong Ki Kim1, Sung Jin Moon1, Yu Seun Kim4, Dae Suk Han1, and Shin-Wook Kang1*
1 Department of Internal Medicine, College of Medicine, Brain Korea 21 for Medical Science, Yonsei University, Seoul, Korea, Republic of
2 Department of Internal Medicine, College of Medicine, Brain Korea 21 for Medical Science, Yonsei University, Seoul, Korea, Republic of; Nephrology and Dialysis Unit, Department of Internal Medicine, The Affiliated Hospital, YanBian University Medical College, JiLin, China
3 Department of Internal Medicine, College of Medicine, Hallym University, Seoul, Korea, Republic of
4 Department of Surgery, College of Medicine, Brain Korea 21 Project Team of Nanobiomaterials for Cell-based Implants, Yonsei University, Seoul, Korea, Republic of
* To whom correspondence should be addressed. E-mail: kswkidney{at}yumc.yonsei.ac.kr.
Previous in vitro studies suggest that the p38 MAPK pathway may be involved in the pathogenesis of diabetic nephropathy(DN), but the consequences of the inhibition of the p38 MAPK pathway have not been well elucidated in diabetic(DM) glomeruli. This study was undertaken to investigate the effect of p38 MAPK inhibitor, FR167653, on fibronectin expression and apoptosis in DM glomeruli and in high glucose-stimulated mesangial cells(MC). In vivo, 32 Sprague-Dawley rats were injected with diluent(C, N=16) or STZ intraperitoneally(DM, N=16). Eight rats from each group were treated with FR167653 for 3 months. In vitro, rat MC were exposed to medium containing 5.6mM glucose(NG) or 30mM glucose(HG) with or without 10-6M FR167653 for 24 hours. Fibronectin mRNA and protein expression were determined by real-time PCR and Western blot, respectively. Western blot for apoptosis-related molecules, TUNEL assay, and Hoechst 33342 staining were performed to determine apoptosis. FR167653 ameliorated the increases in fibronectin/GAPDH mRNA ratio and protein expression in DM glomeruli by 89% and 79% and in HG-stimulated MC by 70% and 91%, respectively(p<0.05). Under diabetic conditions, Bcl-2 protein expression was decreased, while cleaved caspase-3 protein expression was increased(p<0.05), and these changes were inhibited by FR167653 treatment. Apoptotic cells was also significantly increased in DM glomeruli and in HG-stimulated MC(p<0.05), and FR167653 ameliorated these increases in apoptotic cells, both in vivo and in vitro. In conclusion, these findings suggest that the inhibition of the p38 MAPK pathway has beneficial effect on the development of DN by inhibiting the increase in fibronectin expression and apoptosis.
