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Objective:To investigate the protective effect and potential mechanisms of microRNA-26a-5p (miR-26a-5p) on podocyte injury in diabetic kidney disease (DKD).Methods:(1) In vivo experiment: Four-week-old db/db mice were divided into db/db group, db/db+agomir-NC group and db/db+miR-26a-5p agomir group according to random number table method, with 10 mice in each group, and 10 db/m mice of the same week-old were set as normal control group. At the age of 10 weeks, pathological changes were observed through light and electron microscopy. Kidney weight/body weight (KW/BW), urinary albumin to creatinine ratio (ACR), fasting blood glucose (FBG) and other biochemical indicators were also detected. The position and expression of miR-26a-5p in kidney tissue were determined through fluorescence in situ hybridization and quantitative real-time PCR, while the expressions of transient receptor potential cation channel-6 (TRPC6) and Nephrin in kidney tissue were determined by Western blotting and immunohistochemistry. (2) In vitro experiment: The immortalized mouse podocytes (MPC5) were divided into 5 groups: normal glucose group, high mannitol group, high glucose group, high glucose+miR-26a-5p mimic group, and high glucose+mimic-NC group. The expressions of miR-26a-5p, TRPC6 and Nephrin were detected. Luciferase reporter assay was conducted to research the relationship of miR-26a-5p and TRPC6. Results:(1) In vivo experiment: Compared with db/m group, db/db mice exhibited lower KW/BW and disrupted conditions of ACR, FBG, total cholesterol, triglycerides and low density lipoprotein cholesterol (all P<0.01). Increased glomeruli volume, more extracellular matrix deposition, thicker basement membrane and more foot process fusion were observed by light and electron microscope. Increased expression of TRPC6 protein as well as decreased expression of Nephrin protein and miR-26a-5p were detected in kidney tissues of db/db mice ( P<0.05). Compared with db/db+agomir-NC group, db/db mice transfected by miR-26a-5p agomir exhibited less albuminuria, with less protein expression of TRPC6 and more Nephrin in kidney tissue (all P<0.05). (2) In vitro experiment: Compared with normal glucose group, high glucose-treated podocytes exhibited increased expression of TRPC6 ( P<0.05), as well as decreased expression of Nephrin ( P<0.05) and miR-26a-5p ( P<0.01). Compared with high glucose+mimic-NC group, lower expression of TRPC6 and higher expression of Nephrin were detected in podocytes transfected by miR-26a-5p mimic (both P<0.05). Luciferase reporter assay confirmed that miR-26a-5p could regulate the expression of TRPC6 precisely. Conclusions:The expression of miR-26a-5p in podocytes is down-regulated in the context of high glucose and miR-26a-5p protects podocytes from injury via inhibiting the expression of TRPC6 in DKD.
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AIM:To investigate the clinical significance of microRNA-26a-5p (miR-26a-5p)-regulated mye-loid cell leukemia-1 (MCL-1) expression in the development of maternal preeclampsia.METHODS:Plasma and placen-tal tissues were collected from 21 cases of normal pregnancy, 13 cases of maternal gestational hypertension, 15 cases of mild preeclampsia and 26 cases of severe preeclampsia.The levels of plasma and placental miR-26a-5p and placental MCL-1 mRNA were detected by real-time PCR.Western blotting analysis was used to determine the protein expression of placen-tal MCL-1.The clinical significance of the above parameters was also analyzed.RESULTS:miR-26a-5p expression gradu-ally increased(P<0.01) in the 4 groups of maternal plasma and placentas with the disease development, and the mRNA expression of MCL-1 was significantly reduced in the placentas (P<0.01), both showing a significant negative correlation (P<0.01).Meanwhile, the expression of miR-26a-5p and MCL-1 protein in the placental tissues was negatively correla-ted (P<0.01).The miR-26a-5p up-regulation in maternal plasma and placental tissues was negatively correlated with ges-tational age, maternal plasma albumin levels and fetal weight, while it was positively correlated with maternal blood pres-sure and urinary protein level (P<0.01), which was in contrary to the down-regulation of placental MCL-1.CONCLU-SION:Up-regulation of miR-26a-5p is involved in the occurrence and development of preeclampsia by down-regulation of MCL-1.