Inhibition of PLK3 Attenuates Tubular Epithelial Cell Apoptosis after Renal Ischemia–Reperfusion Injury by Blocking the ATM/P53-Mediated DNA Damage Response

Abstract

Objective. Renal ischemia–reperfusion (I/R) injury is a major cause of acute kidney injury (AKI) in transplanted kidneys. This study was aimed at exploring the role of PLK3 (polo-like kinase 3) in renal I/R injury, focusing on its relationship with oxidative stress-induced DNA damage and renal tubular epithelial cell (TEC) apoptosis. Methods. TRAP-seq data from the development dataset GSE52004 and the validation dataset GSE121191 were analyzed using GEO2R. PLK3 overexpression plasmids and targeted silencing siRNAs were used in a model of hypoxia/reoxygenation (H/R) injury, and rAAV-9-PLK3-KD were administered to C57BL/6J mice exposed to I/R injury. The ATM-specific inhibitor KU-60019 was used to block the DNA damage response (DDR). Western blotting was performed to measure DDR- and apoptosis-associated protein expression. Cell viability was measured by CCK-8 reagent, and apoptosis was examined by flow cytometry and TUNEL assay. Furthermore, the fluorescent probes H2DCFH-DA and DHE were used to measure ROS production in vitro. The MDA level and SOD activity were measured to assess oxidative stress in vivo. KIM-1 staining and Scr and BUN were used to evaluate kidney injury. Results. The mRNA and protein levels of PLK3 were markedly increased in the H/R injury and I/R injury models. GO terms showed that PLK3 was mainly involved in oxidative stress and DNA damage after renal I/R injury. Overexpression of PLK3 decreased cell viability and increased apoptosis. In contrast, targeted silencing of PLK3 expression decreased the Bax/Bcl-2 ratio by decreasing P53 phosphorylation, thereby reducing TEC apoptosis. Furthermore, KU-60019 reduced PLK3 activation and DDR-induced apoptosis, while overexpression of PLK3 reversed the mitigating effect of KU-60019 on TEC apoptosis. Similarly, rAAV-9-PLK3 KD mice exhibited a lower rate of TEC apoptosis and milder renal damage after I/R injury. Conclusion. We demonstrate for the first time that PLK3 is involved in oxidative stress-induced DNA damage and TEC apoptosis in renal I/R injury. Inhibition of PLK3 attenuates TEC apoptosis after I/R injury by blocking the ATM/P53-mediated DDR. Therefore, PLK3 may serve as a potential therapeutic target for ischemic AKI.

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“…Due to its participation in the stress response upon environmental stresses and oxidative stress, it is assumed that PLK3 might be mainly involved in regulating the stress response, and the inhibition of PLK3 has been shown to attenuate injury-induced apoptosis in a mouse model of renal ischemia-reperfusion (I/R) injury [ 42 ]. However, besides regulating DNA damage response and apoptosis, PLK3 has also been linked with cell cycle progression by regulating S phase entry [ 39 , 41 ] as well as centrosomal function and the regulation of microtubule dynamics, with its dysregulation resulting in cell cycle arrest and apoptosis [ 43 ].…”

Identification of Key Genes Associated with Heat Stress in Rats by Weighted Gene Co-Expression Network Analysis

“…In reaction to oxidative stress, polo-like protein kinase 3 (Plk3) has been postulated to trigger apoptosis. For example, Deng et al [55] discovered that plk3 played a role in oxidative stress-induced DNA damage and apoptosis, and they found that overexpressing plk3 reduced cell vitality and increased apoptosis, whereas silencing plk3 weakened the apoptotic response. Meanwhile, in another study, Zfp36l1 was able to degrade the mRNA of plk3 through the AU-rich elements in the 3'UTR region [56].…”

TET2 amplifies RIPK3/MLKL necroptosis signal by upregulation of PLK3 to promote UVB-induced skin photodamage

“…It responses to various environmental stresses (51). Studies have proved it to be a tumor suppressor since it blocks the cell proliferation and initiates apoptosis (52,53). Studies have also revealed that PLK3 is a stress response protein linked to DNA damage and that miR-24 directly targets it to restrict the intrinsic growth potential of hair follicle progenitors (54,55).…”