microRNA-215在糖尿病肾病小鼠肾组织中的表达及意义

目的 探讨microRNA-215( miR-215)在糖尿病肾病(DN)小鼠肾组织中的表达变化规律及在DN发病中的作用.方法 选择4周龄的2型糖尿病肾病db/db小鼠(实验组)和db/m小鼠(对照组),采用实时荧光定量PCR法动态检测8、12及16周龄时肾组织miR-215的表达变化；实时荧光定量PCR和Western印迹法、免疫组化法测定连环蛋白β互动蛋白1( CTNNBIP1)的mRNA及蛋白的表达；双荧光素酶报告法确证miR-215对CTNNBIP1表达的直接调控作用.结果 (1)随着周龄的增加,db/db小鼠肾小球逐渐肥大、节段性系膜细胞增生和系膜基质积聚.(2)与同周龄的db/m小鼠比较,8、12及16周龄的db/db小鼠体质量(BW)、血糖( Glu)及24 h尿白蛋白排泄量(UAE)均显著增加(均P＜0.05).(3)随着周龄的增加,db/db小鼠肾脏组织miR-215表达显著高于同周龄的db/m小鼠(P＜0.05).(4)与同周龄的db/m小鼠比较,db/db小鼠肾脏组织CTNNBIP1 mRNA和蛋白均显著降低(均P＜0.05).(5)应用双荧光素酶报告法证实,miR-215可显著抑制CTNNBIP1的表达(P＜0.01).结论 miR-215表达上调可能通过抑制CTNNBIP1的表达参与DN的发生、发展.

Role of microRNA-215 in nephropathy of type 2 diabetic db/db mice

Objective To investigate the renal expression changes of microRNA-215 (miR-215) and its role in diabetic nephropathy of type 2 diabetic db/db mice. Methods Four-week-old diabetic db/db mice and normal control group non-diabetic db/m mice were selected. Real-time PCR was used to detect the relative level of miR-215 at the age of 8, 12 and 16 weeks. Catenin beta interacting protein 1 (CTNNBIP1) mRNA and protein level were measured by real-time PCR, Western blotting and immunohistochemisty. A lueiferase reporter assay was used to determine whether CTNNBIP1 was a direct target of miR-215. Results (1)With the growth of db/db mice, the major pathological characteristics of kidney included glomerular hypertrophy, segmental mesangial cells proliferation and mesangial matrix expansion. (2)Compared with the db/m mice, the db/db mice of 8, 12 and 16 weeks showed obvious increase in body weight（BW）, blood glucose (Glu) and 24 hour urinary albumin excretion (UAE) (P<0.05, respectively). (3)Compared with the db/m mice, special miR-215 was highly expressed in the kidney of db/db mice and was up-regulated significantly according to the development of DN (P<0.05). (4)The mRNA and protein expression of CTNNBIP1 of kidney were consistently down-regulated in db/db mice than those in controls(P<0.05, respectively）. (5)By luciferase reporter, miR-215 could negatively regulate CTNNBIP1 gene by targeting its 3’-UTR sequence (P<0.01). Conclusion High expression level of miR-215 plays a potential role in the initiation and progression of DN by down-regulating the expression of CTNNBIP1.