Genetic and Pharmacological Inhibition of GRPR Protects Against Acute Kidney Injury via Attenuating Renal Inflammation and Necroptosis.

Gastrin-releasing peptide (GRP) binds to its receptor GRPR to regulate multiple biological processes, but the function of GRP/GRPR axis in acute kidney injury (AKI) remains unknown. In the present study, GRPR is highly expressed by tubular epithelial cells (TECs) in patients or mice with AKI. While histone deacetylase 8 may lead to the transcriptional activation of GRPR. Functionally, we uncovered that GRPR was pathogenic in AKI as genetic deletion of GRPR was able to protect mice from cisplatin and ischemic induced AKI. This was further confirmed by specifically deleting the GRPR gene from TECs in GRPR mice. Mechanistically, we uncovered that GRPR was able to interact with TLR4 to activate STAT1 that bound the promoter of MLKL and CCL2 to induce TEC necroptosis, necroinflammation, and macrophages recruitment. This was further confirmed by overexpressing STAT1 to restore renal injury in GRPR mice. Concurrently, STAT1 induced GRP synthesis to enforce the GRP/GRPR/STAT1 positive feedback loop. Importantly, targeting GRPR by lentivirus-packaged shRNA or by treatment with a novel GRPR antagonist RH-1402 was able to inhibit cisplatin-induced AKI. In conclusion, GRPR is pathogenic in AKI and mediates AKI via the STAT1-dependent mechanism. Thus, targeting GRPR may be a novel therapeutic strategy for AKI.