AQP8 Modulates Mitochondrial H₂O₂ Transport to Influence Glioma Proliferation

Abstract

Background

Aquaporin-8 (AQP8) is involved in impacting glioma proliferation and can effect tumour growth by regulating Intracellular reactive oxygen species (ROS) signalling levels. In addition to transporting H₂O₂, AQP8 has been shown to affect ROS signaling, but evidence is lacking in gliomas. In this study, we aimed to investigate how AQP8 affects ROS signaling in gliomas.

Materials and methods

We constructed A172 and U251 cell lines with AQP8 knockdown and AQP8 rescue by CRISPR/Cas9 technology and overexpression of lentiviral vectors. We used CCK-8 and flow cytometry to test cell proliferation and cycle, immunofluorescence and Mito-Tracker CMXRos to observe the distribution of AQP8 expression in glioma cells, Amplex and DHE to study mitochondria release of H₂O₂, mitochondrial membrane potential (MMP) and NAD+/NADH ratio to assess mitochondrial function and protein blotting to detect p53 and p21 expression.

Result

We found that AQP8 co-localised with mitochondria and that knockdown of AQP8 inhibited the release of H₂O₂ from mitochondria and led to increased levels of ROS in mitochondria, thereby impairing mitochondrial function. We also discovered that AQP8 knockdown resulted in suppression of cell proliferation and was blocked at the G0/G1 phase with increased expression of mitochondrial ROS signalling-related p53/p21.

Conclusions

This finding provides further evidence for mechanistic studies of AQP8 as a prospective target for the treatment of gliomas.

Keywords:

• Aquaporin-8
• glioma
• mitochondria
• ROS
• p53/p21

Acknowledgements

The authors thank the works of Brain Science Research Centre of Chongqing Medical University for their help on experimental instrument.

Ethical approval statement

Ethical approval was not required for this research.

Author contributions

Conceptualisation, Z.S.; Software, Z.C., H.Z., Z.G.; Investigation, Z.S., J.L., H.L., L.T.; Supervision, H.S., J.Z, J.X.; Resources, S.G., J.H.; Writing – original draft, Z.S.; Writing – review and editing, S.Z.; Funding acquisition, S.Z. All authors have read and agreed to the published version of the manuscript.

Declaration of interest

The authors declare that there is no conflict of interest.

Data availability statement

The data that support the findings of this study are available on request from the corresponding author.

Additional information

Funding

The project was funded by ShuJuan Zhu [Grant ID: cstc2014jcyjA10028] and Jin Xu [Grant ID: cstc2016jcyjA0229].