PLK2 inhibited oxidative stress and ameliorated hepatic ischemia-reperfusion injury through phosphorylating GSK3β.

Background and aim: Hepatic ischemia-reperfusion (I/R) injury is the primary cause of liver dysfunction and liver failure, commonly occurring in liver transplantation, hepatectomy, and hemorrhagic shock. Polo-like kinase 2 (PLK2), a pivotal regulator of centriole duplication, plays a crucial role in cell proliferation and injury repair. However, the function of PLK2 in hepatic I/R remains unclear.

Methods: The effect of PLK2 was investigated in the mouse hepatic I/R model and the hepatocyte hypoxia-reoxygenation (H/R) model. Liver injury was assessed by serum transaminase and hematoxylin and eosin staining. Cell apoptosis was analyzed using TUNEL analysis and immunoblotting. Inflammatory factors were evaluated by reverse transcription-quantitative polymerase chain reaction. Mice or cultured cells during the I/R or H/R were treated by overexpressing PLK2. ROS fluorescence staining was used to assess oxidative stress injury.

Results: PLK2 was upregulated after hepatic I/R injury. Overexpressed PLK2 significantly improved liver enzyme levels and alleviated liver histological injury. Moreover, PLK2 decreased hepatocyte apoptosis and inhibited the expression of inflammatory factors in liver. Mechanistically, PLK2 increased the phosphorylation of GSK3β and enhanced expression of the antioxidant enzyme HO-1, leading to less ROS production. Inhibition of the HO-1 aggravated ROS generation and abolished the protective effect of PLK2.

Conclusion: Overall, these findings revealed that PLK2 enhanced HO-1 expression and reduced oxidative stress damage in hepatic I/R injury, and this protective effect related to GSK3β activity.