IgA肾病PTEN表达及其对肾间质纤维化的影响

目的： 探讨IgA肾病（IgAN）肾组织中染色体10上缺失的磷酸酶与张力蛋白同源物基因（PTEN）表达及其对肾间质纤维化的影响。方法: 选择IgAN患者47例，并详细收集资料；10例肾脏肿瘤切除后正常远端肾组织作对照。肾小管间质病变程度用Katafuchi等标准分为4组。应用免疫组化SP法检测PTEN、转化生长因子-β1（TGF-β1）、α-平滑肌肌动蛋白（α-SMA）、Ⅲ型胶原（Col Ⅲ）以及原位杂交法检测PTEN mRNA表达。结果: ①IgAN和对照肾组织中PTEN及PTEN mRNA表达部位主要在肾小管上皮细胞胞浆中，肾小球内无或仅有极少量表达。IgAN随肾小管间质病变程度加重，PTEN与PTEN mRNA表达逐渐减少，无病变组明显高于其它3组（均P<0.05）。②IgAN肾组织PTEN与PTEN mRNA表达正相关（P<0.05）；两者分别与eGFR、尿渗透压正相关（P<0.01），与TGF-β1、α-SMA、ColⅢ、24 h尿蛋白排泄量、硬化肾小球数以及血管积分负相关（均P<0.01）。结论: IgAN中TGF-β1可能在基因转录水平下调PTEN表达，诱导肾小管上皮转分化以及细胞外基质的沉积，从而在肾小管间质纤维化过程中起到重要作用。

Effect of tumor suppressor phosphatase and tensin homology deleted in chromosome 10 on renal interstitial fibrosis in IgA nephropathy

AIM: To explore the potential correlation between the expression of phosphatase and tensin homology deleted on chromosome 10(PTEN) and RIF in IgA nephropathy. METHODS: Forty-seven patients diagnosed as primary IgA nephropathy by renal histology were involved. 10 specimens from normal renal tissue of renal carcinoma served as control group. Tubulointerstitial lesion (TIL) was classified by using Katafuchi scale, including no TIL (group I), mild TIL (group II), moderate TIL (group III), severe TIL (group IV). The expressions of PTEN, TGF-β1, α-SMA and ColⅢ in renal tissue were detected by immunohistochemistry. PTEN mRNA was detected by in situ hybridization. RESULTS: Renal tissues from renal biopsy showed abundant expressions of PTEN and PTEN mRNA in endochylema of renal tubular epithelial cells, and negligible expression in glomeruli. With the progress of TIF in IgA nephropathy, the expressions of PTEN and PTEN mRNA decreased gradually (P<0.05). In contrast, the expressions of TGF-β1, α-SMA and ColⅢ increased significantly (P<0.05). The expressions of PTEN and PTEN mRNA in renal tissues were positively with eGFR and urine osmotic pressure (P<0.01), negatively correlated with the expressions of TGF-β1, α-SMA, ColⅢ, urinary protein excretion for 24 h, the rate of sclerosis glomeruli and the scores of vascular lesion (P<0.01). CONCLUSION: These results suggest the loss of PTEN expression in RIF of IgA nephropathy. Moreover, TGF-β signaling induces epithelial to mesenchymal transition and extracellular matrix accumulation possibly through a mechanism dependent on the downregulation of PTEN.