Co-catalpol alleviates fluoxetine-induced main toxicity: Involvement of ATF3/FSP1 signaling-mediated inhibition of ferroptosis

Fluoxetine is often used as a well-known first-line antidepressant. However, it is accompanied with hepatogenic injury as its main organ toxicity, thereby limiting its application despite its superior efficacy. Fluoxetine is commonly traditionally used combined with some Chinese antidepressant prescriptions containing Rehmannia glutinosa (Dihuang) for depression therapy and hepatoprotection. Our previous experiments showed that co-Dihuang can alleviate fluoxetine-induced liver injury while efficiencies, and catalpol may be the key ingredient to characterize the toxicity-reducing and synergistic effects. However, whether co-catalpol can alleviate fluoxetine-induced liver injury and its toxicity-reducing mechanism remain unclear.On the basis of the first recognition of the dose and duration at which pre-fluoxetine caused hepatic injury, co-catalpol's alleviation of fluoxetine-induced hepatic injury and its pathway was comprehensively elucidated.The hepatoprotection of co-catalpol was evaluated by serum biochemical indexes sensitive to hepatic injury and multiple staining techniques for hepatic pathologic analysis. Subsequently, the pathway by which catalpol alleviated fluoxetine-induced hepatic injury was predicted by network pharmacology to be predominantly the inhibition of ferroptosis. These were validated and confirmed in subsequent experiments with key technologies and diagnostic reagents related to ferroptosis. Further molecular docking showed that activating transcription factor 3 (ATF3) and ferroptosis suppressor protein 1 (FSP1) were the the most prospective molecules for catalpol and fluoxetine among many ferroptosis-related molecules. The critical role of ATF3/FSP1 signaling was further observed by surface plasmon resonance, diagnostic reagents, transmission electron microscopy, Western blot, real-time PCR, immunofluorescence, and immunohistochemistry. Results showed that fluoxetine directly bound to ATF3 and FSP1; agonisting ATF3 or blocking FSP1 abolished the alleviation of catalpol on fluoxetine-induced liver injury, and both exacerbated ferroptosis. Moreover, co-catalpol significantly enhanced the antidepressant efficacy of fluoxetine against depressive behaviours in mice.The hepatic impairment properties of fluoxetine were largely dependent on ATF3/FSP1 target-mediated ferroptosis. Co-catalpol alleviated fluoxetine-induced hepatic injury while enhancing its antidepressant efficacy, and that ATF3/FSP1 signaling-mediated inhibition of ferroptosis was involved in its co-administration detoxification mechanism. This study was the first to reveal the hepatotoxicity characteristics, targets, and mechanisms of fluoxetine; provide a detoxification and efficiency regimen by co-catalpol; and elucidate the detoxification mechanism.