Targeting hepatic IRE1a for Treating GDF15-driven Anorexia in Chemotherapy
Anorexia and other side effects of chemotherapy significantly limit the clinical applications of these chemotherapeutic agents, with underlying mechanisms still unclear. A growing body of research reveals that elevated levels of circulating GDF15 after chemotherapy are essential in initiating anorexia and other side effects by activating GFRAL+ neurons in the brainstem. However, the full array of context-dependent transcriptional regulators controlling Gdf15 expression remains to be defined. This study reports that chemotherapy drugs acutely stimulate liver GDF15 production via selective activation of the hepatic stress sensor IRE1a, thereby controlling circulating GDF15 levels. Genetic ablation of hepatic IRE1a reduces circulating GDF15 and alleviates anorexia and body weight loss following chemotherapy drug treatments in tumor-bearing mice. Mechanistically, chemotherapy drugs activate hepatic IRE1a RNase activity to produce the active form of the transcription factor XBP1 to promotes the expression of Gdf15 gene in hepatocytes. Moreover, treatment with pharmacological IRE1a RNase inhibitor effectively suppresses liver Gdf15 expression and circulating GDF15 levels, resulting in improvements in chemotherapy-induced anorexia and body weight loss. Our results reveal a stress-responsive mechanism that mediates communication between the liver and brain. This mechanism can be targeted pharmacologically to alleviate anorexic side effects that accompany chemotherapy-induced body weight loss. Overall design: For the evaluation of chemotherapy effects in healthy mice, the liver samples were collected from the mice 1 day after doxorubicin and chemotherapy. Bulk RNA-seq experiment was performed to analyze gene expression profile in these liver samples. A-Saline B-Cisplatin C-Doxorubicin *Samples do not include information about treatment with doxorubicin.