Expression and role of microRNA-155 in db/db mice / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the expression of microRNA-155 (miR-155) in serum and kidney of C57BLKS/db (db/db) mice and its role in the pathogenesis of diabetic kidney disease (DKD).Methods:The db/db mice ( n=24) were divided into 6, 8, and 10 weeks old groups ( n=8) with age increasing according to the random number table, and C57BL/6 mice of the same age were used as control group. The expression of miR-155 in mouse serum and kidney tissue was determined using real-time quantitative PCR. The mRNA and protein expression of Ets-1, eNOS, AGTR1 in renal tissues was verified by real-time quantitative PCR, Western blotting and immunohistochemistry. Results:Compared with the control group, the expression of miR-155 in serum of db/db mice at 6, 8 and 10 weeks of age were significantly increased (all P<0.01), and the increase of miR-155 was most obvious at 10 weeks of age ( P<0.01). Meanwhile the expression of miR-155 in kidney tissues of 6, 8 and 10 weeks old db/db mice was significantly up-regulated (all P<0.01), and the highest expression of miR-155 was at 10 weeks of age ( P<0.01). Immunohistochemistry showed that Ets-1, eNOS and AGTR1 were localized in glomerular endothelial cells. The results of real-time quantitative PCR showed that the mRNA expression of Ets-1, eNOS and AGTR1 were down-regulated in the kidney tissues of db/db mice at 6, 8 and 10 weeks of age compared to the control(all P<0.05), and the level of down-regulation was the most obvious at 10 week. Western blotting results showed that there was no significant change in Ets-1, eNOS and AGTR1 in 6-week-old db/db mice compared to the control group; the eNOS protein expression was down-regulated at 8 weeks of age ( P<0.05); the expression of AGTR1 protein was down-regulated ( P<0.05), and the protein expression of Ets-1 and eNOS were significantly down-regulated at 10-week age (both P<0.01). Conclusions:The expression of miR-155 in serum and kidney tissues of db/db mice increases during the progression of DKD, while the expression of miR-155 target genes Ets-1, eNOS and AGTR1 decreases with the progression of DKD. MiR-155 may participate in the development and progression of DKD by inhibiting its target genes Ets-1, eNOS and AGTR1, affecting endothelial cell function.