Huang Jau-Shyang, Chuang Lea-Yea, Guh Jinn-Yuh, Chen Chorng-Jia, Yang Yu-Lin, Chiang Tai-An, Hung Min-Yuan, Liao Tung-Nan
Department of Biological Science and Technology, Chung Hwa College of Medical Technology, 89 Wen-Hwa, 1st Street, Jen-Te Hsiang, Tainan Hsien 717, Taiwan, Republic of China.
J Am Soc Nephrol. 2005 Aug;16(8):2318-29. doi: 10.1681/ASN.2005010030. Epub 2005 Jun 15.
Renal interstitial fibrosis is believed to play a key role in the development of diabetic nephropathy (DN), and advanced glycation end-products (AGE) may contribute importantly to this. Recent reports have shown that nitric oxide (NO) is closely linked to the renal interstitial fibrosis of DN. In this study, the mechanisms by which NO and its downstream signals mediate the AGE-induced proliferative response in normal rat kidney fibroblasts (NRK-49F) are examined. AGE decreased NO production, cyclic guanosine 5'monophosphate (cGMP) synthesis, and cGMP-dependent protein kinase (PKG) activation time- and dose-dependently. These effects were not observed when cells were treated with nonglycated BSA. NO and inducible nitric oxide synthase (iNOS) stimulated by NO donors S-nitroso-N-acetylpenicillamine (SNAP)/sodium nitroprusside (SNP) and PKG activator 8-para-chlorophenylthio-cGMP (8-pCPT-cGMP) prevented both AGE-induced proliferation and Janus kinase 2 (JAK2)-signal transducers and activators of transcription 5 (STAT5) activation but not p42/p44 mitogen-activated protein kinase (MAPK) activation. The ability of NO-PKG to inhibit AGE-induced cell cycle progression was verified by the observation that SNAP, SNP, and 8-pCPT-cGMP inhibited both cyclin D1 and cdk4 activation. Furthermore, induction of NO-PKG significantly increased p21Waf1/Cip1 expression in AGE-treated NRK-49F cells. The data suggest that the NO-PKG pathway inhibits AGE-induced proliferation by suppressing activation of JAK2-STAT5 and cyclin D1/cdk4 and induction of p21Waf1/Cip1.
肾间质纤维化被认为在糖尿病肾病（DN）的发展中起关键作用，而晚期糖基化终产物（AGE）可能对此有重要影响。最近的报道表明，一氧化氮（NO）与DN的肾间质纤维化密切相关。在本研究中，研究了NO及其下游信号介导AGE诱导的正常大鼠肾成纤维细胞（NRK-49F）增殖反应的机制。AGE呈时间和剂量依赖性地降低NO生成、环磷酸鸟苷（cGMP）合成以及cGMP依赖性蛋白激酶（PKG）激活。用非糖化牛血清白蛋白处理细胞时未观察到这些效应。由NO供体S-亚硝基-N-乙酰青霉胺（SNAP）/硝普钠（SNP）刺激产生的NO和诱导型一氧化氮合酶（iNOS）以及PKG激活剂8-对氯苯硫基-cGMP（8-pCPT-cGMP）可阻止AGE诱导的增殖以及Janus激酶2（JAK2）-信号转导和转录激活因子5（STAT5）激活，但不能阻止p42/p44丝裂原活化蛋白激酶（MAPK）激活。通过观察到SNAP、SNP和8-pCPT-cGMP抑制细胞周期蛋白D1和细胞周期蛋白依赖性激酶4（cdk4）激活，证实了NO-PKG抑制AGE诱导的细胞周期进程的能力。此外，在AGE处理的NRK-49F细胞中，NO-PKG的诱导显著增加了p21Waf1/Cip1表达。数据表明，NO-PKG途径通过抑制JAK2-STAT5和细胞周期蛋白D1/cdk4的激活以及p21Waf1/Cip1的诱导来抑制AGE诱导的增殖。
