Germacrone Alleviates Cisplatin‐Induced Nephrotoxicity by Activating <scp>PI3K</scp> /Akt Signaling, Inhibiting Ras/ <scp>MAPK</scp> Signaling, and Regulating Macrophage Polarization

Acute kidney injury (AKI) is a serious complication of cisplatin chemotherapy, requiring new preventive therapies. Germacrone, a sesquiterpenoid derived from Rhizoma Curcuma, has multiple pharmacological effects, including anti-inflammatory, antiapoptotic, and antioxidant effects. The current study aimed to investigate the effect and mechanism of germacrone on AKI. Single high-dose and multiple low-dose cisplatin-induced AKI and AKI-chronic kidney disease (CKD) transition mouse models were used to determine the preventive effect of germacrone, with the mechanism explored in HK-2 and Raw264.7 cells. A breast cancer tumor-bearing model was developed to determine whether the nephron-protective effects of germacrone affect the anticancer properties of cisplatin. Here, we found that germacrone significantly alleviated AKI and fibrosis in cisplatin-treated mice, as demonstrated by decreased serum creatinine and blood urea nitrogen (BUN) levels and improved renal pathology. Germacrone attenuated cisplatin-induced apoptosis and inflammation in vivo and in vitro. RNA sequencing revealed that germacrone restored cisplatin-induced gene dysregulation and regulated inflammation and apoptosis through the PI3K/AKT and Ras/MAPK pathways. Inhibition of these pathways abrogated the renoprotective effect of germacrone in vitro. Moreover, germacrone reduced macrophage activation and induced an M2-dominant shift in macrophage polarization in the kidneys and Raw264.7 cells via similar pathways. Furthermore, germacrone protected the kidneys without affecting the chemotherapeutic effects of cisplatin on a mouse model of breast cancer. Therefore, germacrone is expected to have universal renoprotective effects across different AKI models and a tumor-bearing model through similar signaling pathways, suggesting its potential as a clinical adjuvant therapy for reducing nephrotoxicity in patients receiving cisplatin chemotherapy.