Oxygen-glucose Deprivation In Astrocytes Research Articles

Inhibiting Caspase-12 Mediated Inflammasome Activation protects against Oxygen-Glucose Deprivation Injury in Primary Astrocytes.

Stroke is one of the leading causes of death worldwide. Accumulating evidence suggests that NLRP3 inflammasome activation plays an important role in ischemic stroke injury. However, the existence of the NLRP3 inflammasome in astrocytes remains controversial. In this study, we demonstrated the presence of the NLRP3 inflammasome in primary mouse astrocytes and investigated the role of caspase-12 in NLRP3 inflammasome activation and cell injury in an in vitro astrocyte oxygen-glucose deprivation (OGD) model. Astrocytes exposed to 2, 3, and 4 h of OGD exhibited increased cell injury and apoptosis, and the protein levels of caspase-12, cleaved caspase-3, NLRP3 inflammasome components, and IL-1β were also significantly elevated. Interestingly, pretreatment with the caspase-12-specific inhibitor Z-ATAD-FMK attenuated cell injury and apoptosis and decreased the levels of NLRP3, caspase-1, IL-1β, and cleaved caspase-3 in the OGD group. In conclusion, Z-ATAD-FMK protected astrocytes against OGD-induced cell death and inhibited NLPR3-inflammasome activation. Our results indicate that caspase-12 and its potential regulation of NLRP3 inflammasome activation might be a promising target for treatment of ischemic stroke.

Propofol attenuates excessive autophagy induced by astrocyte oxygen glucose deprivation injury

目的： 探讨异丙酚对星形胶质细胞氧糖剥夺/复糖复氧损伤的影响。 方法： 利用新生24 h内的BALB/c鼠婴，取脑皮层星形胶质细胞原代培养后，氧糖剥夺2 h，复糖复氧24 h；CCK8检测星形胶质细胞细胞活力；免疫印迹法（Western blot）检测自噬相关蛋白的表达。 结果： 与对照组相比，氧糖剥夺损伤时细胞活力下降，随着异丙酚浓度的升高，异丙酚可增加氧糖剥夺细胞损伤活力；氧糖剥夺损伤时自噬相关蛋白Beclin1表达和LC3-Ⅱ/LC3-Ⅰ比值增加，随着异丙酚浓度的提升，Beclin1表达和LC3-Ⅱ/LC3-Ⅰ比值减少。 结论： 异丙酚能够减轻星形胶质细胞氧糖剥夺损伤引起的过度自噬，从而减轻星形胶质细胞氧糖剥夺损伤。.

The protective effect of 2-(2-benzonfu-ranyl)-2-imidazoline against oxygen-glucose deprivation in cultured rat cortical astrocytes

Astrocytes play a pivotal role in neuronal survival in the setting of post-ischemic brain inflammation, but the astrocyte-derived mediators of ischemic brain injury remain to be defined. 2-(2-Benzofu-ranyl)-2-imidazoline (2-BFI) is a newly discovered ligand for high-affinity imidazoline I2 receptors (I2Rs) mainly located on the mitochondrial outer membrane in astrocytes. We previously reported that in a rat model of cerebral ischemia-reperfusion injury, 2-BFI limits infarct volume, reduces neurological impairment scores, and inhibits neuronal apoptosis in the ischemic penumbra. This study was performed to clarify the underlying mechanism in an astrocyte oxygen-glucose deprivation (OGD) model. The results show that 2-BFI reduces lipid peroxidation and inhibits mitochondria apoptotic pathways.

RIG-I contributes to the innate immune response after cerebral ischemia.

BackgroundFocal cerebral ischemia induces an inflammatory response that when exacerbated contributes to deleterious outcomes. The molecular basis regarding the regulation of the innate immune response after focal cerebral ischemia remains poorly understood.MethodsIn this study we examined the expression of retinoic acid-inducible gene (RIG)-like receptor-I (RIG-I) and its involvement in regulating inflammation after ischemia in the brain of rats subjected to middle cerebral artery occlusion (MCAO). In addition, we studied the regulation of RIG-I after oxygen glucose deprivation (OGD) in astrocytes in culture.ResultsIn this study we show that in the hippocampus of rats, RIG-I and IFN-α are elevated after MCAO. Consistent with these results was an increased in RIG-I and IFN-α after OGD in astrocytes in culture. These data are consistent with immunohistochemical analysis of hippocampal sections, indicating that in GFAP-positive cells there was an increase in RIG-I after MCAO. In addition, in this study we have identified n-propyl gallate as an inhibitor of IFN-α signaling in astrocytes.ConclusionOur findings suggest a role for RIG-I in contributing to the innate immune response after focal cerebral ischemia.

Sulfiredoxin-1 attenuates oxidative stress via Nrf2/ARE pathway and 2-Cys Prdxs after oxygen-glucose deprivation in astrocytes.

Sulfiredoxin-1 (Srxn1), an endogenous antioxidant protein, is involved in keeping the balance of the cell's oxidation/reduction and can resist oxidative stress. However, the exact antioxidant effects of Srxn1 remain fully unclear. The study aims to examine the effects of Srxn1 on oxidative stress and explore the potential mechanisms in astrocytes with 6h/oxygen-glucose deprivation (OGD), 24h/respiration. In the study, silencing Srxn1 was performed before exposure to 6h/OGD, 24h/respiration in primary astrocytes. Decreased cell viability and increased cellular damage measured by CellTiter 96H AQueous Non-Radioactive Cell Proliferation Assay (MTS) and lactate dehydrogenase (LDH) were observed in Srxn1 silencing astrocytes. In addition, Srxn1 silencing resulted in a decrease in both intracellular superoxide dismutase (SOD) and glutathione (GSH). NF-E2-related factor 2 (Nrf2), a transcription factor known to influence susceptibility to oxidative stress, upregulated Srxn1 expression during oxidative stress caused by OGD in the astrocytes. Electromobility shift assay (EMSA) demonstrated a decreased binding of Nrf2 to oligomers containing Srxn1 ter-specific antioxidant response element (ARE)-binding site in Nrf2 silencing astrocytes. We also found that a reduction of peroxiredoxin (Prdx)-SO3 was closely dependent on Srxn1. In addition, 2-Cys Prdxs protein levels were increased in the astrocytes exposed to OGD, as evaluated by immunoblot analysis. All taken together, the study suggested that silencing Srxn1 would result into increasing sensitivity to OGD-induced oxidative stress injury in astrocytes. Furthermore, Nrf2/ARE pathway was involved into Srxn1, playing its antioxidant protection against oxidative stress, all of which would provide a novel therapeutic theory for treating acute ischemic brain injury.

Geldanamycin reduces necrotic and apoptotic injury due to oxygen-glucose deprivation in astrocytes

Recent data show that geldanamycin can protect the brain against stroke in vivo, and this may be due to induction of heat shock proteins. Our previous results show that heat shock protein 70 expression by retroviral transfection protects astrocytes from necrotic injury by combined oxygen-glucose deprivation, an in vitro model of ischemia. This study tested the ability of geldanamycin to protect astrocytes from either necrotic or apoptotic injury induced by oxygen-glucose deprivation. Astrocytes were pre-treated with 0.1 µg ml-1 geldanamycin in the medium 4, 8, or 16 h before as well as during oxygen-glucose deprivation. Increased protein levels of heat shock protein 70 were observed after 8 h pre-treatment with geldanamycin and increased further at 16 h pre-treatment, as detected by immunoblotting. Geldanamycin pre-treatment protected mature astrocytes from necrotic cell death and young astrocytes from apoptotic death. Geldanamycin protection of astrocytes against in vitro ischemia is likely due to upregulation of heat shock protein 70.