c-MYC-induced long noncoding RNA MEG3 aggravates kidney ischemia–reperfusion injury through activating mitophagy by upregulation of RTKN to trigger the Wnt/β-catenin pathway

Abstract

Ischemia–reperfusion injury (IRI)-induced acute kidney injury (AKI) is a life-threatening disease. The activation of mitophagy was previously identified to play an important role in IRI. Maternally expressed 3 (MEG3) can promote cerebral IRI and hepatic IRI. The present study was designed to study the role of MEG3 in renal IRI. Renal IRI mice models were established, and HK-2 cells were used to construct the in vitro models of IRI. Hematoxylin–eosin staining assay was applied to reveal IRI-triggered tubular injury. MitoTracker Green FM staining and an ALP kit were employed for detection of mitophagy. TdT-mediated dUTP-biotin nick-end labeling assay was used to reveal cell apoptosis. The results showed that renal cortex of IRI mice contained higher expression of MEG3 than that of sham mice. MEG3 expression was also elevated in HK-2 cells following IRI, suggesting that MEG3 might participate in the development of IRI. Moreover, downregulation of MEG3 inhibited the apoptosis of HK-2 cells after IRI. Mitophagy was activated by IRI, and the inhibition of MEG3 can restore mitophagy activity in IRI-treated HK-2 cells. Mechanistically, we found that MEG3 can bind with miR-145-5p in IRI-treated cells. In addition, rhotekin (RTKN) was verified to serve as a target of miR-145-5p. MEG3 upregulated RTKN expression by binding with miR-145-5p. Further, MEG3 activated the Wnt/β-catenin pathway by upregulation of RTKN. The downstream effector of Wnt/β-catenin pathway, c-MYC, served as the transcription factor to activate MEG3. In conclusion, the positive feedback loop of MEG3/miR-145-5p/RTKN/Wnt/β-catenin/c-MYC promotes renal IRI by activating mitophagy and inducing apoptosis, which might offer a new insight into the therapeutic methods for renal IRI in the future.

A novel approach to identify the mechanism of miR-145-5p toxicity to podocytes based on the essential genes targeting analysis

“…miR-145-5p has been reported to be dysregulated and involved in kidney injuries. 17 , 18 To determine whether supplement of miR-145-5p could alleviate kidney injury in mouse models, we purified the EVs from miR-145-5p transfected Jurkat or HEK293 cells and obtained the miR-145-5p-enriched EVs ( Figure S1 ). We first tested the miR-145-5p EV samples for toxicity or side effects on healthy control mice by administering miR-145-5p EVs intravenously every other day for a total of 3 times.…”

“…miR-145-5p dysregulation has been shown to be involved in kidney injury by mediating the effect of MALAT1 17 and MEG3 18 on kidney. Recently, we investigated whether systemically administered miR-145-5p could mitigate kidney injury in mouse models, and, unexpectedly, we found that treatment of normal control mice with extracellular vesicles (EVs) loaded with miR-145-5p resulted in albuminuria and podocyte foot process effacement.…”

microRNA-145-5p attenuates acute lung injury via targeting ETS2

“…Construction of ALI model miR-145-5p expression is decreased in renal ischemia-reperfusion injury [29], and ETS2 is up-regulated in ARDS [14]. miR-145-5p, ETS2, TGF-β1 and Smad2/3 levels, as well as the phosphorylated (p)-Smad2/3 in rats with ALI were detected by RT-qPCR and Western blot.…”

Potentially Functional microRNA-mRNA Regulatory Networks in Intestinal Ischemia-Reperfusion Injury: A Bioinformatics Analysis

“…Through GO and KEGG analysis, identified the main biological function of Co-DE mRNAs. There are several signaling pathways involved in ischemia-reperfusion injury, including Wnt signaling pathway, 34 PI3K/Akt signaling pathway, 35 JAK/STAT signaling pathway, 32 and cAMP signaling pathway 36 among others. The result of KEGG analysis verified the association of Co-DE mRNAs with the above signaling pathways, such as cAMP pathway and PI3K/Akt pathway.…”