Melatonin Alleviates Heme-Induced Ferroptosis Via Activating the Nrf2/HO-1 Pathway in Neurons

Background: Melatonin is able to alleviate the intracerebral hemorrhage (ICH), but its detail functions are poorly understood. As an iron-contained compound in hemoglobin, heme is involved in nerve injury after ICH. In this study, we aimed to investigate the roles and mechanism of melatonin in heme-induced injury after ICH. Methods: C57BL/6 mice were intracranially injected with heme, and then received melatonin treatment. Behavior Tests (mNSS, forelimb placing and corner turn tests), H&E staining, Nissl Staining and Prussian Blue Staining were recuited to evaluate mice’s brain tissue injury. In vitro, the HT-22 cells were stimulated with heme, and the cell viability was determined by crystal violet staining. The iron contents were determined in heme-treated brain and cells, and the levels of 4-hydroxynonenal (4-HNE), malonaldehyde (MDA) were assessed by ELISA. Quantitative PCR (qPCR) were applied to investigate the mRNA levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Immunoblotting was recruited to analyze protein expression of glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), Nrf2 and HO-1. Last, the small interfering RNA (siRNA) was used to knock down Nrf2 in the HT-22 cells. Results: Melatonin treatment alleviated the heme-induced neural function injuries, manifested by improving behavior in the mice. Moreover, melatonin decreased the cell death, iron concentration, and the MDA and 4-HNE elevations, and reversed the reduced expressions of GPX4, SLC7A11, Nrf2 and HO-1 induced by heme in vitro and in vivo. These results indicated that melatonin could improve the ferroptosis induced by heme. In addition, we found that Nrf2 knockdown attenuated the therapeutic effect of melatonin on neuronal ferroptosis induced by heme. Conclusions: In general, melatonin alleviates heme-induced ferroptosis by activating the Nrf2/HO-1 pathway, which implied that melatonin is a promising treatment for the ferroptosis in ICH.