Protective effect of Xingnaojing injection on ferroptosis after cerebral ischemia injury in MCAO rats and SH-SY5Y cells.

Xingnaojing（XNJ）injection is a traditional Chinese medicine injection with neuroprotective effect, which has been widely used in the treatment of stroke for many years. This study aimed to explore the potential mechanism of XNJ in cerebral ischemia mediated by ferroptosis using proteomics and in vivo and in vitro experiments. After the rat model of middle cerebral artery occlusion (MCAO) was successfully established, they were randomly divided into model, XNJ, and deferoxamine (DFO) group. Triphenyl tetrazolium chloride (TTC) staining, Hematoxylin and eosin (H&E), and Nissl staining were used to observe the infarct area, pathological changes and the degree of neuronal apoptosis of rat brain. Proteins extracted from rat brain tissues were analyzed by quantitative proteomics using tandem mass tags (TMT). Western blotting and immunohistochemical assessment were used to measure the expression of ferroptosis-related proteins. In vitro, the SH-SY5Y cells were subjected to hypoxia (37°C/5% CO2/1% O2) for 24 h to observe the survival rate, and detect the reactive oxygen species (ROS) content and ferroptosis-related proteins. In TTC and H&E experiments, we found that XNJ drug treatment reduced the infarct volume and brain tissue damage in MCAO rats. Nissl staining also showed that compared with MCAO group rats, the Nissl bodies of brain tissue after XNJ drug intervention were clear with a 3.54-fold increased times, suggesting that XNJ improved cerebral infraction, and neurological deficits in MCAO rats. Proteomics identified 101 intersected differentially expressed proteins (DEPs). According to the bioinformatics analysis, these DEPs were closely related to ferroptosis. Further research indicated that MCAO-induced cerebral ischemia was alleviated by upregulating recombinant glutathione peroxidase 4 (GPX4), ferroportin (FPN) expression, Heme oxygenase-1 (HO-1) expression, and downregulating cyclooxygenase-2 (COX-2), transferring receptor (TFR) and divalent metal transporter-1 (DMT1) expression after XNJ treatment. In addition, in vitro experiment indicated that XNJ improved the survival rate of hypoxia-damaged SH-SY5Y cells. XNJ increased the level of GPX4 and inhibited the protein expression of COX-2 and TFR after cell hypoxia. Moreover, different concentrations of XNJ (0.25%, 0.5%, 1%) reduced the ROS content of hypoxic cells, suggesting that XNJ could inhibit hypoxia-induced cell damage by regulating the expression of ferroptosis-related proteins and decreasing the production of ROS. XNJ could promote the recovery of neurological function in MCAO rats and hypoxia SH-SY5Y cells by regulating ferroptosis.

Liu H ，An N ，Wang L ，Li Y ，Song K ，Sun Y ，Gao Y ... -  《-》

Rehmannioside A improves cognitive impairment and alleviates ferroptosis via activating PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway after ischemia.

Rehmannioside A is derived from Rehmannia glutinosa Libosch, which is widely used as an important ingredient in diverse traditional Chinese medicines to treat diseases caused by "kidney deficiency" such as cerebral arteriosclerosis, aging-related stroke and dementia in China. Recent studies have proved that Rehmannia glutinosa Libosch and Rehmannioside A can improve memory capability and recover nerve damage. To investigate the effect of Rehmannioside A on cognitive impairment after ischemia in rats and SH-SY5Y cells, and further evaluate the anti-oxidative and anti-ferroptosis mechanisms. Differentially expressed proteins (DEPs) in patients after cerebral ischemic stroke were revealed by a RayBio protein array. Cognitive impairment model was established by middle cerebral artery occlusion and reperfusion (MCAO) 14 days in rats. Rehmannioside A was administered intraperitoneally injection at dose of 80 mg/kg. The SH-SY5Y cells were exposed to H2O2 for 24 h and treated with Rehmannioside A (80 μM) for 24 h. The neuroprotecion of Rehmannioside A were evaluated by infarct volume (TTC), neurological defects (Garcia score) and learning memory (Morris water maze test) in vivo, and cell viability (CCK-8 or LDH) in vitro. Superoxide dismutase (SOD), malondialdehyde (MDA) and myeloperoxidase (MPO) activity of rats, glutathione (GSH), oxidized glutathione (GSSG) and nicotinamide adenine dinucleotide phosphate (NADPH) of cells were detected by biochemical assay. Intracellular reactive oxygen species (ROS) were measured by DCFH-DA assay. Myeloperoxidase (MPO), PI3 kinase (PI3K), p-PI3K, Akt, p-Akt, heme oxygenase-1 (HO-1), nuclear factor-E2-related factor 2 (Nrf2), SLC7A11, glutathione peroxidase 4 (GPX4) of the cerebral cortex in rats or SH-SY5Y cells were examined by western blotting. Compared with model group, the cognitive impairment and neurological deficits of Rehmannioside A group were significantly improved, and the cerebral infarction was reduced in MCAO rats. Moreover, the cell viability obviously increased and the H2O2-induced toxicity was reduced in Rehmannioside A group. Further research indicated that the expression of p-PI3K, p-Akt, nuclear Nrf2, HO-1 and SLC7A11 in Rehmannioside A group was significantly higher than model group. Rehmannioside A has neuroprotection effect and improves cognitive impairment after cerebral ischemia by inhibiting ferroptosis and activating PI3K/AKT/Nrf2 and SLC7A11/GPX4 signaling pathway. These findings provide valuable insight into the pathogenesis and therapeutic target of ischemic stroke.

Fu C ，Wu Y ，Liu S ，Luo C ，Lu Y ，Liu M ，Wang L ，Zhang Y ，Liu X ... -  《-》

Rhein attenuates cerebral ischemia-reperfusion injury via inhibition of ferroptosis through NRF2/SLC7A11/GPX4 pathway.

Liu H ，Zhang TA ，Zhang WY ，Huang SR ，Hu Y ，Sun J ... -  《-》

Loureirin C inhibits ferroptosis after cerebral ischemia reperfusion through regulation of the Nrf2 pathway in mice.

Ischemic stroke (IS) is considered as a serious cerebral vascular disease. Ferroptosis is a novel type of regulated cell death (RCD), that closely related to the occurrence and progress of IS. Loureirin C, a type of dihydrochalcone compound derived from the Chinese Dragon's blood (CDB). The effective components extracted from CDB have shown neuroprotective effects in ischemia reperfusion models. However, the role of Loureirin C in mice after IS is not well understood. Thus, it is worth to identify the effect and mechanism of Loureirin C on IS. The present research aims to prove the existence of ferroptosis in IS and explore whether Loureirin C can inhibit ferroptosis by regulating nuclear factor E2 related factor 2 (Nrf2) pathway in mice and exert neuroprotective effects on IS models. Middle cerebral artery occlusion and reperfusion (MCAO/R) model was established to evaluate the occurrence of ferroptosis and the potential Loureirin C brain-protective effect in vivo. The analysis of free iron, glutamate content, reactive oxygen species (ROS) and lipid peroxidation levels, along with transmission electron microscope (TEM) was applied to prove the existence of ferroptosis. The function of Loureirin C on Nrf2 nuclear translocation was verified by immunofluorescence staining. In vitro, primary neurons and SH-SY5Y cells were processed with Loureirin C after oxygen and glucose deprivation-reperfusion (OGD/R). ELISA kits, western blotting, co-immunoprecipitation (Co-IP) analysis, immunofluorescence, and quantitative real-time PCR were devoted to proving the neuroprotective effects of Loureirin C on IS via regulating ferroptosis and Nrf2 pathways. The results showed that Loureirin C not only dramatically alleviated brain injury and inhibited neurons ferroptosis in mice after MCAO/R, but also dose-dependently reduce ROS accumulation in ferroptosis after OGD/R. Further, Loureirin C inhibits ferroptosis by activating Nrf2 pathway, and promoting nuclear translocation of Nrf2. Besides, Loureirin C increases heme oxygenase 1 (HO-1), quinone oxidoreductase 1 (NQO1) and glutathione peroxidase 4 (GPX4) content after IS. Intriguingly, the anti-ferroptosis effect of Loureirin C is weakened by Nrf2 knockdown. Our discoveries first revealed that the inhibitory action of Loureirin C on ferroptosis may greatly depend on its adjusting effect on the Nrf2 pathway, suggesting that Loureirin C could act as a novel anti-ferroptosis candidate and play a therapeutic role in IS. These novel discoveries on the role of Loureirin C on IS models reveal an innovative method that may contribute to neuroprotection for the prevention of IS.

Liu Y ，Mi Y ，Wang Y ，Meng Q ，Xu L ，Liu Y ，Zhou D ，Wang Y ，Liang D ，Li W ，Li N ，Hou Y ... -  《-》

Butylphthalide inhibits ferroptosis and ameliorates cerebral Ischaemia-Reperfusion injury in rats by activating the Nrf2/HO-1 signalling pathway.

This study aims to investigate whether butylphthalide can inhibit ferroptosis and ameliorate cerebral ischaemia-reperfusion (I/R) injury in rats by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) / heme oxygenase-1 (HO-1) signalling pathway, known for its antioxidative and cytoprotective properties. Middle cerebral artery occlusion reperfusion (MCAO/R) rat models were established. Male rats were randomly divided into five groups: a sham-operated group (sham), MCAO/R group, MCAO/R ​+ ​ML385 (Nrf2-specific inhibitor) group, MCAO/R ​+ ​NBP (butylphthalide) group and MCAO/R ​+ ​ML385 ​+ ​NBP group. The effect of butylphthalide on cerebral I/R injury was evaluated using neurological deficit scores. The expression levels of Nrf2, HO-1, glutathione peroxidase 4 (GPX4), acyl-CoA synthetase long-chain family member 4 (ACSL4) and transferrin receptor 1 (TfR1) protein were detected using Western blot. Moreover, the expression levels of GPX4, HO-1 and TfR1 mRNA were determined through real-time fluorescence quantitative reverse transcription polymerase chain reaction. The distribution of Nrf2, HO-1, GPX4 and TfR1 was detected using immunohistochemical staining. The levels of iron and related lipid peroxidation indexes, such as reduced glutathione, reactive oxygen species, malondialdehyde and nitric oxide, were measured using a kit. The changes in mitochondria were observed through transmission electron microscopy. Butylphthalide treatment significantly improved neurological dysfunction, reduced cerebral infarction volume and mitigated histopathological damage in MCAO/R rats. It induced the nuclear translocation of Nrf2 and upregulated HO-1 expression, which was attenuated by ML385. Butylphthalide also attenuated lipid peroxidation, iron accumulation and mitochondrial damage induced by MCAO/R. The expression of GPX4, ACSL4 and TfR1 proteins, as well as their mRNA levels, was modulated through butylphthalide treatment, with improvements observed in mitochondrial morphology. Butylphthalide exerts neuroprotective effects by attenuating neurological dysfunction and ferroptosis in MCAO/R rats through the activation of the Nrf2/HO-1 pathway and inhibition of lipid peroxidation and iron accumulation.

Sun M ，Chen J ，Liu F ，Li P ，Lu J ，Ge S ，Wang L ，Zhang X ，Wang X ... -  《-》