Repurposing Aprepitant: Can it protect against doxorubicin-induced Chemobrain beyond its antiemetic role?

The substance P (SP) and neurokinin-1 receptor (NK-1R) axis is crucial in numerous pathological processes, including inflammation, stress responses, pain perception, and vomiting. Consequently, aprepitant, an NK-1R blocker, is used as an antiemetic in chemotherapy, including the use of doxorubicin (DOX), but whether aprepitant can also assuage DOX-mediated chemobrain remains to be unveiled. Here, we scrutinized the potential neuroprotective effect and underlying mechanisms of aprepitant using DOX-induced chemobrain model, where rats were allocated into 4 groups (control, aprepitant, DOX, and DOX+ aprepitant). Cognitive deficits were assessed through behavioral tests and hippocampal structural alterations were determined by H&E and toluidine blue staining. Biochemical measurements were performed using ELISA, real-time quantitative PCR, western blotting, and immunohistochemical methods. Aprepitant improved cognitive responses, and hippocampal morphology, enhancing the presence of intact neurons. At the molecular tier, aprepitant significantly reduced hippocampal contents of SP and the inflammatory markers NF-κB and IL-1β. Additionally, it signified its antioxidant and antiapoptotic capacities by downregulating cleaved caspase-3 protein expression and curbing the content of malondialdehyde but boosted those of glutathione and Bcl-2. Aprepitant also downregulated the expression of miR-146a and turned off the endoplasmic reticulum (ER) stress cascade PERK/eIF-2α/ATF-4/CHOP. To recapitulate, aprepitant demonstrates a neuroprotective effect against DOX-mediated chemobrain by alleviating inflammatory, oxidative, and apoptotic responses, partly by reducing SP, ER stress, and miR-146a. These findings not only underscore the potential of aprepitant as a neuroprotective agent but also offer new understanding of the mechanisms behind chemobrain, leading to better therapeutic strategies for cancer patients.