Protective effects of ginsenoside Rb3 on oxygen and glucose deprivation-induced ischemic injury in PC12 cells

The serum/glucose deprivation (SGD)-induced cell death in cultured PC12 cells represents a useful in vitro model for the study of brain ischemia and neurodegenerative disorders.Nigella sativa L. and its active component, thymoquinone (TQ) have been known as a source of antioxidants. In the present study, the protective effects of N. sativa and TQ on cell viability and reactive oxygen species (ROS) production in cultured PC12 cells were investigated under SGD conditions. PC12 Cells were pretreated with different concentrations of N. sativa extract (15.62–250 μg/ml) and TQ (1.17–150 μM) for 2 h and then subjected to SGD for 6 or 18 h. Cell viability was quantitated by MTT assay. Intracellular ROS production was measured by flow cytometry using 2’,7’-dichlorofluorescin diacetate (DCF-DA) as a probe. SGD induced significant cells toxicity after 6, 18, or 24 h (p < 0.001). Pretreatment with N. sativa (15.62–250 μg/ml) and TQ (1.17–37.5 μM) reduced SGD-induced cytotoxicity in PC12 cells after 6 and 18 h. A significant increase in intracellular ROS production was seen following SGD (p < 0.001). N. sativa (250 μg/ml, p < 0.01) and TQ (2.34, 4.68, 9.37 μM, p < 0.01) pretreatment reversed the increased ROS production following ischemic insult. The experimental results suggest that N. sativa extract and TQ protects the PC12 cells against SGD-induced cytotoxicity via antioxidant mechanisms. Our findings might raise the possibility of potential therapeutic application of N. sativa extract and TQ for managing cerebral ischemic and neurodegenerative disorders.

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High-density lipoprotein protects cardiomyocytes against necrosis induced by oxygen and glucose deprivation through SR-B1, PI3K, and AKT1 and 2

Biochemical Journal ◽

10.1042/bcj20170703 ◽

2018 ◽

Vol 475 (7) ◽

pp. 1253-1265 ◽

Cited By ~ 11

Author(s):

Kristina K. Durham ◽

Kevin M. Chathely ◽

Bernardo L. Trigatti

Keyword(s):

Cell Death ◽

High Density Lipoprotein ◽

Ischemia Reperfusion ◽

Density Lipoprotein ◽

Glucose Deprivation ◽

High Density ◽

Dependent Manner ◽

Protective Effects ◽

Oxygen And Glucose Deprivation ◽

Ventricular Cardiomyocytes

The cardioprotective lipoprotein HDL (high-density lipoprotein) prevents myocardial infarction and cardiomyocyte death due to ischemia/reperfusion injury. The scavenger receptor class B, type 1 (SR-B1) is a high-affinity HDL receptor and has been shown to mediate HDL-dependent lipid transport as well as signaling in a variety of different cell types. The contribution of SR-B1 in cardiomyocytes to the protective effects of HDL on cardiomyocyte survival following ischemia has not yet been studied. Here, we use a model of simulated ischemia (oxygen and glucose deprivation, OGD) to assess the mechanistic involvement of SR-B1, PI3K (phosphatidylinositol-3-kinase), and AKT in HDL-mediated protection of cardiomyocytes from cell death. Neonatal mouse cardiomyocytes and immortalized human ventricular cardiomyocytes, subjected to OGD for 4 h, underwent substantial cell death due to necrosis but not necroptosis or apoptosis. Pretreatment of cells with HDL, but not low-density lipoprotein, protected them against OGD-induced necrosis. HDL-mediated protection was lost in cardiomyocytes from SR-B1−/− mice or when SR-B1 was knocked down in human immortalized ventricular cardiomyocytes. HDL treatment induced the phosphorylation of AKT in cardiomyocytes in an SR-B1-dependent manner. Finally, chemical inhibition of PI3K or AKT or silencing of either AKT1 or AKT2 gene expression abolished HDL-mediated protection against OGD-induced necrosis of cardiomyocytes. These results are the first to identify a role of SR-B1 in mediating the protective effects of HDL against necrosis in cardiomyocytes, and to identify AKT activation downstream of SR-B1 in cardiomyocytes.

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