转录因子Ets-1在2型糖尿病肾病中的表达及其意义

Expression and significance of transcription factor Ets-1 in type 2 diabetic nephropathy

目的:观察转录因子Ets-1、基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶-2组织抑制剂(TIMP-2)、α-平滑肌肌动蛋白(α-SMA)、波形蛋白(vimentin)和Ⅳ型胶原(ColⅣ)在2型糖尿病肾病(DN)中的表达及探讨其意义。方法:糖尿病肾病组25例;轻微病变性肾病(MCD)20例设为对照组。采用免疫组织化学染色,观察各实验组肾组织内Ets-1、MMP-2、TIMP-2、α-SMA、vimentin及ColⅣ的表达,并行免疫双染共定位分析。结果:25例DN患者中,男15例,女10例;年龄35～67岁。对照组20例MCD患者中,男12例,女8例;年龄18～46岁。与对照组相比,DN组肾小球内Ets-1表达显著性增加(P<0.05),肾小管间质纤维化区域内Ets-1表达亦明显增加(P<0.05);DN组MMP-2在肾小球及肾小管间质内的表达显著性增加(P<0.05);TIMP-2在肾小球及肾小管间质内的表达也明显增加(P<0.05),肾小球及肾小管间质内MMP-2/TIMP-2比值却显著性降低,差异有统计学意义(P<0.05)。与对照组相比,DN组肾小球内α-SMA、vimentin及ColⅣ表达明显增加(P<0.05),肾小管间质内α-SMA及ColⅣ表达亦明显增加(P<0.05),vimentin在肾小管间质内表达则显著性增加(P<0.01)。免疫双染显示,2型DN肾组织内大多数Ets-1阳性细胞同时出现MMP-2阳性表达,而α-SMA阳性细胞同时具有ColⅣ阳性表达。结论:Ets-1转录因子可能通过调节MMP-2/TIMP-2系统平衡,影响ECM沉积,在2型DN基质重塑过程中起关键性作用。

Objective： Ets-1 proto-oncogene is a member of the transcriptional factor family and was identified by homology to the V-ets oncogene. It was recently demonstrated that Ets-1 protein interacts with the promoter region of the genes coding for proteinases, including matrix metalloproteinases （MMPs） , suggesting that it may play an important role in the regulation of MMPs expression. The role of the Ets-1 proto-oncogene in diabetic nephropathy （DN）, where extracellular matrix （ECM） accumulation is observed, remains undefined. To elucidate the role of Ets-1 in DN,we studied the expression pattern of Ets-1 ,Matrix metaloproteinase-2 （MMP-2）, Tissue Inhibitors of Metalloproteinase-2 （ TIMP- 2）, a- smooth muscle action （ a- SMA） and type 1V collagen （ Col IV ） in matrix remodeling in Type 2 DN. Methods： 25 cases of renal biopsy sections diagnosed as DN were selected. Type 2 diabetes was defined according to Standards of Medical Care in diabetes. 2007/ADA. Meanwhile, 20 cases of renal biopsy specimens diagnosed as minor glomerular abnormalities （minimal change disease, MCD ） were simultaneously studied as controls. Pathological classifications were made according to the WHO criteria of 1982 for renal pathology or the modified WHO criteria of 1995. Histopathological findings were identified under light microscopy. Using immunohistochemistry and double immunostaining, we investigated the expression of Ets- I, MMP-2, TIMP-2, a-SMA, vimentin and collagen type IV （Col IV ）in type 2 DN. The experimental data was statistically analyzed and statistical significance was achieved at corrected P 〈 0. 05. Results： 25 DN cases （ male 15 ,female 10） between the ages of 35 and 67 years were observed. 20 MCD patients （male 12, female 8）, aged 18-46 years, were noted. By immunnohistochemistry, the expression of Ets-1 in glomeruli and tubulointerstitium was significantly increased in the kidneys obtained from DN group compared with MCD groups （ P 〈 0.05 ）. Compared to MCD patients, increased expression of MMP-2, TIMP-2, a-SMA, vimentin and Col IV in glomeruli was observed in DN patients （P 〈 0.05 ）. Specially, the ratio of MMP-2 and TIMP-2 in glomeruli and tubulointerstitium from 2 Type DN compared with control group （P 〈 0. 05 ）. Meanwhile, overexpression of a- SMA and deposition of Col IV in tubulointersitium was observed in the DN patients （ P 〈 0. 05 ）, the expression of vimentin in tubulointerstitium was significantly increased （P 〈 0. 05）. By double immunostaining, a-SMA positive cells were frequently found to co-express Col IV in glomemli and tubulointersitium of Type 2 DN patients. Increased expression of MMP-2 concorded with the increased expression of Ets-1 in the kidneys obtained from Type 2 DN. Conclusion ： Ets- 1 transcription factor may regulate the balance of MMP-2 and TIMP-2 enzyme system, and closely associated with increased deposition of ECM. Ets-1 plays a critical role in matrix remodeling in human Type 2 DN.