Background
Hypoxia-mediated inflammation plays a crucial role in renal ischaemia-reperfusion (IR)-induced acute kidney injury (AKI) and may influence renal graft survival, with no available pharmacological treatments. Here we investigate the protective effects and mechanism of roxadustat (FG-4592), a hypoxia-inducible factor stabilizer, against renal IR injury.
Conclusion
FG-4592-conveyed protection against AKI might be mediated by the induction of CD73 and the suppression of the AIM2 inflammasome, which may provide a novel therapeutic method for the treatment of AKI.
Methods
The protein expression levels of CD73 and AIM2 inflammasome complex were examined in kidney biopsy specimens of AKI and post-renal transplantation (PRT) patients. The effects of FG-4592 on CD73 and absent in melanoma 2 (AIM2) inflammasome components were examined in IR mice (right nephrectomy, followed by 30 min of unilateral renal ischaemia and reperfusion for 24 h), and some of the model mice received intraperitoneal administrations of adenosine 5'-(α,β-methylene)diphosphate sodium salt, which is an inhibitor of CD73. The function of FG-4592 was also investigated in vitro with HK-2 cells.
Results
In the AKI and PRT patients, the protein expression of AIM2 complex [AIM2-apoptosis-associated speck-like protein (ASC)-cleaved caspase-1) increased and the activation of CD73 signalling pathway was detected as well. The pretreatment of FG-4592 improved the creatinine elevation and renal tubular injuries induced by ischaemia. What's more, the administration of FG-4592 significantly enhanced CD73 synthesis in mouse kidney but suppressed the activation of the AIM2 inflammasome [decreased AIM2, ASC, caspase-1, interleukin (IL)-1β and IL-18 levels]. Notably, the renoprotection of FG-4592 and the inhibition of AIM2 were abolished by the CD73 inhibitor.