Noh Hyunjin, Ha Hunjoo, Yu Mi Ra, Kim Young Ok, Kim Ji Hye, Lee Hi Bahl
Hyonam Kidney Laboratory, Soon Chun Hyang University, Seoul, Korea.
Perit Dial Int. 2005 Jan-Feb;25(1):38-47.
To demonstrate the presence of an independent renin-angiotensin system (RAS) in the peritoneum and to determine the role of locally produced angiotensin (Ang) II in high glucose-induced upregulation of transforming growth factor (TGF)-beta1 and fibronectin by human peritoneal mesothelial cells (HPMC).
In cultured HPMC, the expression of mRNAs for angiotensinogen, angiotensin-converting enzyme (ACE), Ang II type 1 receptor (AT1), and TGF-beta1 was evaluated by real-time polymerase chain reaction; ACE, AT1, and fibronectin proteins by Western blot analysis; and Ang I, Ang II, and TGF-beta1 proteins by ELISA. Dichlorofluorescein (DCF)-sensitive cellular reactive oxygen species (ROS) were measured by fluorometry.
HPMC constitutively expressed all the components of RAS, and 50 mmol/L D-glucose (high glucose) significantly increased angiotensinogen, ACE, and AT1 mRNAs and ACE, AT1, and Ang II proteins. Ang II increased TGF-beta1 and fibronectin protein expression and DCF-sensitive cellular ROS. Losartan prevented Ang II-induced increase in cellular ROS. Both losartan and captopril inhibited high glucose-induced upregulation of TGF-beta1 and fibronectin expression in HPMC in a dose-dependent manner. Antioxidant catalase and NADPH oxidase inhibitor diphenyleneiodinium effectively inhibited Ang II-induced TGF-beta1 and fibronectin protein expression.
The present data demonstrate that HPMC constitutively express RAS, that Ang II produced by HPMC mediates high glucose-induced upregulation of TGF-beta1 and fibronectin expression, and that Ang II-induced TGF-beta1 and fibronectin expression in HPMC is mediated by NADPH oxidase-dependent ROS. These data suggest that locally produced Ang II and ROS in the peritoneum may be potential therapeutic targets in peritoneal fibrosis during long-term peritoneal dialysis.
证实腹膜中存在独立的肾素 - 血管紧张素系统（RAS），并确定局部产生的血管紧张素（Ang）II在高糖诱导人腹膜间皮细胞（HPMC）转化生长因子（TGF）-β1和纤连蛋白上调中的作用。
在培养的HPMC中，通过实时聚合酶链反应评估血管紧张素原、血管紧张素转换酶（ACE）、血管紧张素II 1型受体（AT1）和TGF-β1的mRNA表达；通过蛋白质印迹分析评估ACE、AT1和纤连蛋白蛋白；通过酶联免疫吸附测定评估血管紧张素I、血管紧张素II和TGF-β1蛋白。通过荧光法测量二氯荧光素（DCF）敏感的细胞活性氧（ROS）。
HPMC组成性表达RAS的所有成分，50 mmol/L D-葡萄糖（高糖）显著增加血管紧张素原、ACE和AT1的mRNA以及ACE、AT1和血管紧张素II蛋白。血管紧张素II增加TGF-β1和纤连蛋白蛋白表达以及DCF敏感的细胞ROS。氯沙坦可防止血管紧张素II诱导的细胞ROS增加。氯沙坦和卡托普利均以剂量依赖方式抑制高糖诱导的HPMC中TGF-β1和纤连蛋白表达上调。抗氧化剂过氧化氢酶和NADPH氧化酶抑制剂二苯基碘鎓有效抑制血管紧张素II诱导的TGF-β1和纤连蛋白蛋白表达。
目前的数据表明，HPMC组成性表达RAS，HPMC产生的血管紧张素II介导高糖诱导的TGF-β1和纤连蛋白表达上调，并且血管紧张素II诱导的HPMC中TGF-β1和纤连蛋白表达由NADPH氧化酶依赖性ROS介导。这些数据表明，腹膜中局部产生的血管紧张素II和ROS可能是长期腹膜透析期间腹膜纤维化的潜在治疗靶点。
