Involvement of androgen receptor (AR)/microRNA-21 axis in hypoxia/reoxygenation-induced apoptosis of mouse renal tubular epithelial cells.

The function of androgen receptor (AR)/microRNA-21 (miR-21) axis in tumor development was well investigated. However, the roles of the axis performed in hypoxia/reoxygenation (H/R)-induced apoptosis of mouse renal tubular epithelial cells (RTECs) is not known. In this study, H/R-induced apoptosis of RTECs was established to evaluate the role of miR-21-AR axis. The protocol of 8-h hypoxia and 24-h reoxygenation were selected to produce H/R injury. Our data showed that H/R increased miR-21 and caspase-3 expression, reduced the expression AR and programmed cell death protein 4 (PDCD4). By contrast, AR-siRNA increased H/R-induced apoptosis, and promoted caspase-3 expression, but reduced PDCD4 expression (vs. H/R group). pre-miR-21 reduced, while antagomiR-21 promoted apoptosis and PDCD4 expression in H/R-induced RTECs. Moreover, pre-miR-21 promoted, while antagomiR-21 reduced caspase-3 expression in H/R-induced RTECs. Together, H/R increased miRNA-21 and reduced AR expression, then regulating PDCD4- and caspase-3-dependent apoptosis. AR/miR-21 axis could be a potential therapeutic target for the kidney ischemia injury.

Pioglitazone protects tubular cells against hypoxia/reoxygenation injury through enhancing autophagy via AMPK-mTOR signaling pathway.

Pioglitazone (Pio), a peroxisome proliferators-activated receptor-γ (PPAR-γ) agonist, may protect against renal ischemia/reperfusion injury (IRI). Recent studies have shown that autophagy plays a protective role in IRI. We aimed to evaluate whether autophagy was involved in pioglitazone-induced protection during tubular cell hypoxia/reoxygenation (H/R). Normal rat kidney proximal tubular cells NRK-52E were subjected to H/R injury, and they were divided into 6 groups: control, control + Pio, H/R, H/R + Pio, H/R + MA, H/R + MA + Pio. Autophagy-related proteins were primarily assessed by Western blot and TUNEL was performed to assess cell apoptosis. Our results showed pioglitazone pretreatment had a cytoprotective effect against H/R injury. The H/R + Pio group had an increased ratio of LC3-II to LC3-I and increased Beclin-1, decreased p62. Pioglitazone also reduced apoptosis and enhanced cell survival while inducing autophagy. Correspondingly, autophagy inhibition with 3-MA alleviated this protective effect. Furthermore, pioglitazone-induced enhancement of autophagy could be related to increased AMP-activated protein kinase (AMPK) phosphorylation and decreased Mammalian target of rapamycin (mTOR) phosphorylation. Thus, pioglitazone pretreatment protects against H/R injury by enhancting autophagy through the AMPK-mTOR signaling pathway.

Pioglitazone Attenuates Reoxygenation Injury in Renal Tubular NRK-52E Cells Exposed to High Glucose via Inhibiting Oxidative Stress and Endoplasmic Reticulum Stress.

Renal ischemia-reperfusion injury is a major cause of acute kidney injury. In the present study, we investigated the effects of pioglitazone on hypoxia/reoxygenation (H/R) injury in rat renal tubular epithelial cells (RTECs) under normal- (NG) or high-glucose (HG) culture conditions via evaluating oxidative stress and endoplasmic reticulum stress (ERS). The RTECs (NRK-52E cells) were divided into six groups as follows: NG group, HG group, NG + H/R group, HG + H/R group, NG + Pio + H/R group, and HG + Pio + H/R group, among which cells in H/R groups were subjected to 4 h of hypoxia followed by 12 h of reoxygenation. After that, the cells were evaluated using the Cell Counting Kit-8 assay for the determination of their viability and flow cytometry assay for the detection of apoptosis. The levels of superoxide dismutase (SOD), glutathione reductase (GSH), catalase (CAT), and malondialdehyde (MDA) were determined via colorimetric chemical assays. In addition, the expression of ERS-associated proteins, i.e. ATF4, ATF6, GRP78, and CHOP, was determined via western blotting. A HG environment could reduce the viability and increase the apoptotic rate of NRK-52E cells with increased MDA levels and decreased SOD, CAT, and GSH levels, and upregulate the expression of ERS-associated proteins, i.e. ATF4, ATF6, and GRP78. H/R injury could further aggravate changes in the above indicators, but pioglitazone could significantly reverse such changes and alleviate cell injury. Thus, Pioglitazone exhibits a cytoprotective effect on RTECs against H/R injury under NG or HG culture conditions by inhibiting oxidative stress and ERS.

LncRNA MEG3 inhibits the progression of prostate cancer by modulating miR-9-5p/QKI-5 axis.

This study was designed to detecting the influences of lncRNA MEG3 in prostate cancer. Aberrant lncRNAs expression profiles of prostate cancer were screened by microarray analysis. The qRT-PCR and Western blot were employed to investigating the expression levels of lncRNA MEG3, miR-9-5p and QKI-5. The luciferase reporter assay was utilized to testifying the interactions relationship among these molecules. Applying CCK-8 assay, wound healing assay, transwell assay and flow cytometry in turn, the cell proliferation, migration and invasion abilities as well as apoptosis were measured respectively. LncRNA MEG3 was a down-regulated lncRNA in prostate cancer tissues and cells and could inhibit the expression of miR-9-5p, whereas miR-9-5p down-regulated QKI-5 expression. Overexpressed MEG3 and QKI-5 could decrease the abilities of proliferation, migration and invasion in prostate cancer cells effectively and increased the apoptosis rate. On the contrary, miR-9-5p mimics presented an opposite tendency in prostate cancer cells. Furthermore, MEG3 inhibited tumour growth and up-regulated expression of QKI-5 in vivo. LncRNA MEG3 was a down-regulated lncRNA in prostate cancer and impacted the abilities of cell proliferation, migration and invasion, and cell apoptosis rate, this regulation relied on regulating miR-9-5p and its targeting gene QKI-5.