过氧亚硝基阴离子通过JAK/STAT信号途径促进系膜细胞纤连蛋白的合成

Upregulation of Fibronectin by Peroxynitrite in Mesangial Cell via the JAK/STAT Signaling Pathways

氧化应激是糖尿病肾病的重要发病机制之一。过氧亚硝基阴离子(peroxynitrite,ONOO–)是参与氧化应激损伤的重要成员,与糖尿病及其并发症密切相关。该文观察高糖环境下ONOO–对系膜细胞合成纤连蛋白(fibronectin,FN)的影响,并探讨其作用机制。实验中,人肾小球系膜细胞分为4组:正常对照组、高糖组、高糖+尿酸组及高糖+AG490组。培养12,24,48 h后收集细胞及其上清液、并提取细胞总蛋白。采用酶联免疫吸附实验(ELISA)检测细胞上清液中FN的含量,采用免疫细胞化学和Western blot检测NT总蛋白(ONOO–生成的生物标志物)、p-JAK2及p-STAT3蛋白的表达。结果显示,与同期正常组相比,高糖组NT总蛋白、p-JAK2及p-STAT3的表达及FN含量明显增高(P<0.05),并且随着时间的延长表达逐渐增多,以48 h组最为显著;高糖+尿酸组,NT、p-JAK2、p-STAT3及FN较高糖组明显减少(P<0.05);高糖+AG490组,p-JAK2、p-STAT3及FN较高糖组明显减少(P<0.05),但NT表达与高糖组差异无统计学意义(P>0.05)。由此可见,高糖环境下系膜细胞中存在ONOO–的过量表达,ONOO–通过JAK/STAT信号途径促进系膜细胞FN的合成。

Oxidative stress is one of the important underlying mechanism of diabetic nephropathy（DN） development and progression.Peroxynitrite（ONOO–） plays a very important role in the pathogenesis caused by oxidative stress and has been demonstrated to be involved in diabetes and its complications.In our study,we observed the effect of ONOO– on fibronectin（FN） generation in glomerular mesangial cells（MC） and explored its mechanism.The human glomerular mesangial cells（HMC） were divided into four groups： NG group,HG group,HG＋UA group,and HG＋AG490 group.Then,HMCs were harvested and the total protein was extracted at 12,24,48 h after stimulation;meanwhile,the medium was collected for detecting the protein level of FN by enzyme-linked immunosorbent assay（ELISA）.The expression of NT total protein（a marker for ONOO–）,p-JAK2,p-STAT3 were examined by immunocytochemistry and Western blot.The results showed that in HG group,the content of FN and the expression of NT,p-JAK2,p-STAT3 all increased significantly compared with NG group at the corresponding time（P0.05）,meanwhile,the above protein all increased in a time course manner and reached to highest level at 48 h after stimulation;in HG＋UA group,the content of FN and the expression of NT,p-JAK2,p-STAT3 were lower than HG group（P0.05）;in HG＋AG490 group,all above protein except NT decreased significantly compared with HG group（P0.05）,there was no obvious difference of NT expression between HG＋AG490 group and HG group（P0.05）.These demonstrated that the excessive of ONOO– in high glucose environment could upregulate FN generation in MC via JAK/STAT signaling pathways.