Remimazolam Suppresses Oxidative Stress and Apoptosis in Cerebral Ischemia/Reperfusion Injury by Regulating AKT/GSK-3β/NRF2 Pathway.

The mechanism of remimazolam, a benzodiazepine that activates γ-aminobutyric acid a (GABAa) receptors, in cerebral ischemia/reperfusion (I/R) injury is not well understood. Therefore, we explored whether remimazolam activates protein kinase B (AKT)/glycogen synthase kinase-3β (GSK-3β)/nuclear factor erythroid 2-related factor 2 (NRF2) to attenuate brain I/R injury in transcerebral I/R-injured rats and transoxygenic glucose deprivation/reperfusion (OGD/R)-injured SY5Y cells. Remimazolam was added at the beginning of cell and rat reperfusion, and the PI3K/AKT inhibitor LY294002 was added to inhibit the AKT/GSK-3β/NRF2 pathway 24 h before cellular OGD/R treatment and 30 min before rat brain I/R treatment. The viability and apoptosis rate of SY5Y cells, neurological deficit score, cerebral infarction volume and morphological changes of rat brain cells as well as the protein expression of Bax, Bcl2, Caspase 3, Cleaved-Caspase 3 and the number of TdT-mediated dUTP Nick-End Labeling (TUNEL)-positive cells in the penumbral region were detected. Reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), NRF2, heme oxygenase 1 (HO-1), AKT, P-AKT, GSK-3β, P-GSK-3β protein expression, and nuclear translocation of NRF2 were measured in cell and animal assays. Reduced SY5Y cell viability and increased apoptosis caused by OGD/R injury, elevated neurological deficit scores and cerebral infarct volume induced by brain I/R injury in rats, cerebral cell injury, as well as elevated Bax, Cleaved-Caspase 3, decreased Bcl2, and increased number of TUNEL-positive cells in rat brain tissue were all moderated by remimazolam. Decreased GSH-Px, SOD and Elevated MDA, ROS induced by OGD/R-injured SY5Y cells and brain I/R-injured rats were moderated by remimazolam. Meanwhile, remimazolam increased NRF2, HO-1, P-AKT, P-GSK-3β, and the nuclear accumulation of NRF2. The PI3K/AKT inhibitor LY294002 reversed the role of remimazolam in brain I/R injury. This study demonstrates that remimazolam activates the AKT/GSK-3β/NRF2 pathway, thereby attenuating oxidative stress and apoptosis to protect against brain I/R injury.

Duan M ，Yu N ，Liu J ，Zhao Y ，Zhang J ，Song S ，Wang S ... -  《Drug Design Development and Therapy》

Esketamine at a Clinical Dose Attenuates Cerebral Ischemia/Reperfusion Injury by Inhibiting AKT Signaling Pathway to Facilitate Microglia M2 Polarization and Autophagy.

This study aimed to assess the protective effect of a clinical dose esketamine on cerebral ischemia/reperfusion (I/R) injury and to reveal the potential mechanisms associated with microglial polarization and autophagy. Experimental cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in adult rats and simulated by oxygen-glucose deprivation (OGD) in BV-2 microglial cells. Neurological and sensorimotor function, cerebral infarct volume, histopathological changes, mitochondrial morphological changes, and apoptosis of ischemic brain tissues were assessed in the presence or absence of esketamine and the autophagy inducer rapamycin. The expression of biomarkers related to microglial M1 and M2 phenotypes in the ischemic brain tissues was determined by immunofluorescence staining and RT-qPCR, and the expression of proteins associated with autophagy and the AKT signaling pathway in the ischemic brain tissues was assayed by Western blotting. Esketamine alone and esketamine combined with rapamycin alleviated neurological impairment, improved sensorimotor function, decreased cerebral infarct volume, and mitigated tissue injury in the MCAO rats. Importantly, esketamine promoted microglial phenotypic transition from M1 to M2 in both the MCAO rats and the OGD-treated BV-2 microglia, induced autophagy, and inactivated AKT signaling. Furthermore, the effects of esketamine were enhanced by addition of autophagy inducer rapamycin. Esketamine at a clinical dose attenuates cerebral I/R injury by inhibiting AKT signaling pathway to facilitate microglial M2 polarization and autophagy. Furthermore, esketamine combined autophagy inducer can provide an improved protection against cerebral I/R injury. Thus, this study provides new insights into the neuroprotective mechanisms of esketamine and the potential therapeutic strategies of cerebral I/R injury.

Gao Y ，Li L ，Zhao F ，Cheng Y ，Jin M ，Xue FS ... -  《Drug Design Development and Therapy》

20(R)-ginsenoside Rg3 protects against focal cerebral ischemia‒reperfusion injury by suppressing autophagy via PI3K/Akt/mTOR signaling pathway.

This study aimed to investigate the effect of 20(R)-ginsenoside Rg3 on autophagy induced by cerebral ischemia‒reperfusion injury (CIRI) in rats and explore its regulation of the PI3K/Akt signaling pathway. Middle cerebral artery occlusion/reperfusion (MCAO/R) in male rats was injected intraperitoneally with 20(R)-ginsenoside Rg3 (5, 10, 20 mg/kg) 12 h before modeling, 2 h after ischemia and 12 h after reperfusion. Neurobehavioral and neuronal morphological changes were detected 24 h after brain I/R. In vitro, the OGD/R-induced injury model is replicated in PC12 cells and different concentrations of 20(R)-ginsenoside Rg3 are administered to observe its effects on cell viability and autophagy and PI3K/Akt/mTOR-related protein expression. Our findings suggest that treatment with 20 mg/kg 20(R)-ginsenoside Rg3 significantly attenuated the neuronal injury, as evidenced by a decreased number of damaged neurons, reduced dissolution of Nissl corpuscles, a fewer autophagosomes, and downregulated expression of Beclin1 and LC3-II/I compared with the MCAO/R group. Furthermore, 20(R)-ginsenoside Rg3 treatment significantly upregulated the expression of p62, p-PI3K, p-AKT, and p-mTOR. In vitro, 20(R)-ginsenoside Rg3 significantly improved the survival rate of cells following OGD/R and markedly attenuated the LY294002 and OGD/R-induced upregulation of Beclin1 and LC3 gene expression. Moreover, 20(R)-ginsenoside Rg3 could rescued the LY294002 and OGD/R-induced downregulation of p62, p-PI3K, p-AKT, and p-mTOR expression. 20(R)-ginsenoside Rg3 attenuates neuronal injury and motor dysfunction following ischemia-reperfusion by inhibiting the activation of autophagy, and its mechanism is related to the upregulation of the PI3K/Akt/mTOR signaling pathway.

Tao D ，Li F ，Zhang X ，Guo H ，Yang R ，Yang Y ，Zhang L ，Shen Z ，Teng J ，Chen P ，He B ... -  《-》

[Tanshinone Ⅱ_A exerts anti-hepatocellular carcinoma effects by inhibiting oxidative stress via PI3K/Akt and Nrf2/HO-1 signaling pathway].

Fang M ，Huang DR ，Zhang JW ，Liao WJ ，Wu F ，Liu YW ... -  《-》

BAK ameliorated cerebral infarction/ischemia-reperfusion injury by activating AMPK/Nrf2 to inhibit TXNIP/NLRP3/caspase-1 axis.

Cerebral ischemia/reperfusion (I/R) injury is a serious vascular disease with extremely high mortality and disability rate. Bakuchiol (BAK) was found in leaves and seeds of Psoralea corylifolia Linn and has been shown to decrease inflammation and reduce oxidative stress, while the mechanism of BAK in ameliorating cerebral I/R injury remains unclear. Middle cerebral artery occlusion reperfusion (MACO/R) was used to establish mouse model. The protective effect of BAK in MCAO/R mices was detected by performing neurological deficit testing, TTC staining, and H&E staining. Oxygen/glucose deprivation and reperfusion (OGD/R) was used to stimulate SH-SY5Y cells in vitro. Protein expression was detected by western blotting, gene expression was detected by quantitative real-time polymerase chain reaction and apoptosis was detected by immunofluorescence. Our study indicated that BAK protected ischemia-reperfusion injury in MACO/R mice, and upregulated superoxide dismutase (SOD) and the catalase (CAT) enzyme activity. BAK also inhibited the expression of TNF-α, IL-1β, IL-6, and IL-18 and suppressed apoptosis and pyroptosis both in MACO/R mice and in OGD/R SH-SY5Y cells. Further results showed that BAK could suppress TXNIP, ASC, NLRP3, and caspase-1 mRNA levels to reverse assembly of inflammasome. And BAK could also upregulate the expression of phosphorylated AMP-activated protein kinase (AMPK) and nuclear factor erythroid 2-related factor (Nrf2). In addition, Nrf2 inhibitor ML385 reversed the BAK induced reduction of TXNIP, ASC, NLRP3, and the AMPK inhibitor also abolished BAK' the effect on the regulation of Nrf2, TXNIP, ASC, NLRP3, caspase-1, and pro-inflammatory cytokines. In conclusion, BAK, found in leaves and seeds of Psoralea corylifolia Linn, could ameliorated cerebral I/R injury through activating AMPK/Nrf2 to inhibit NLRP3 inflammasome, which might present new therapeutic strategy for cerebral I/R injury.

Xu YW ，Yao CH ，Gao XM ，Wang L ，Zhang MX ，Yang XD ，Li J ，Dai WL ，Yang MQ ，Cai M ... -  《-》