Long Noncoding RNA GSTM3P1 Induces mir-668 Degradation to Promote Ischemic AKI
- AKI: Mechanisms - II
November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
- Wei, Qingqing, Augusta University, Augusta, Georgia, United States
- Huo, Emily Xingbao, Augusta Preparatory Day School, Martinez, Georgia, United States
- Dong, Zheng, Augusta University, Augusta, Georgia, United States
Long non-coding RNAs (lncRNAs) play pivotal roles in ischemic acute kidney injury (AKI). Our study has identified a lncRNA, GSTM3P1, to be induced by hypoxia and to significantly enhance renal proximal tubular cell apoptosis post ATP depletion. Its mouse homologue, gstm2-ps1, exhibited a similar injurious role and induced in C57BL/6 mouse proximal tubules after 30-minute ischemia and 3-hour reperfusion. Proximal tubular specific depletion of gstm2-ps1 significantly protected mice from ischemic AKI. Our research also suggests a potential mechanism of GSTM3P1 to target a renal protective microRNA mir-668 by co-precipipation in the RNA-induced silencing complex.
A binding site of mir-668 in GSTM3P1 was confirmed through luciferase assay. However, unlike the routine lncRNA/microRNA sponge and neutralization, GSTM3P1 overexpression resulted in the degradation of mature mir-668 without affecting its primary transcript or precursor. Mutation of the mir-668 binding site in GSTM3P1 counteracted the mir-668 degradation. Thus, we hypothesized that GSTM3P1 induces mir-668 degradation through target-directed microRNA degradation (TDMD), a new regulation pathway for lncRNAs to suppress microRNAs.
Accordingly, an HEK cell line with ZSWIM8 (a key TDMD complex component) knockout was established. In comparison to the wild type HEK cells, ZSWIM8 knockout hindered the mature form mir-668 degradation by GSTM3P1. Furthermore, to protect kidneys from ischemic AKI, we tested the effect of gstm2-ps1 knockdown. In vitro in cultured mouse proximal tubular cells (BUMPT), gstm2-ps1 siRNAs significantly suppressed ATP depletion-induced apoptosis. In vivo, C57BL/6 male mice were treated with negative control or gstm2-ps1 siRNAs and subjected to 25-minute bilateral kidney ischemia and 48-hour reperfusion injury. Compared to the negative control group, gstm2-ps1 knockdown exhibited significantly protection by reducing BUN and serum creatine levels. The histological examination indicated profound suppression of renal tubular necrosis and apoptosis, and a substantial decrease in renal tubular NGAL induction post injury.
In conclusion, lncRNA GSTM3P1/gstm2-ps1 contributes to renal proximal tubular cell death and ischemic AKI by binding to and inducing mir-668 degradation via TDMD. GSTM3P1/gstm2-ps1 can be a potential therapeutic target for mitigating ischemic AKI.
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