NDRG2 regulates glucose metabolism and ferroptosis of OGD/R‐treated astrocytes by the Wnt/β‐catenin signaling

Abstract

AbstractIschemic stroke is one main type of cerebrovascular disorders with leading cause of death and disability worldwide. Astrocytes are the only nerve cell type storing glycogen in the brain, which regulate the glucose metabolism and handle the energy supply and survive of neurons. Astrocyte ferroptosis contributes to neuron injury in brain disorders. N‐myc downstream‐regulated gene 2 (NDRG2) has been implicated in the progression of brain diseases, including ischemic stroke. However, whether NDRG2 could affect the glucose metabolism and ferroptosis of astrocytes during ischemic stroke remains largely unknown. Mouse astrocytes were treated with oxygen‐glucose deprivation/reoxygenation (OGD/R) to establish the in vitro model. Glial fibrillary acidic protein, NDRG2, Wnt3a and β‐catenin expression levels were detected by immunofluorescence staining and western blot analyses. Glucose metabolism was investigated by glucose uptake, lactate production, nicotinamide adenine dinucleotide phosphate hydrogen/nicotinamide adenine dinucleotide phosphate (NADPH/NADP+), ATP and glycolysis enzymes (HK2, PKM2 and lactate dehydrogenase A [LDHA]) levels. Ferroptosis was assessed via reactive oxygen species (ROS), glutathione (GSH), iron and ferroptosis‐related markers (GPX4 and PTGS2) contents. Glycolysis enzymes and ferroptosis‐related markers levels were measured via western blot. NDRG2 expression was elevated in OGD/R‐induced astrocytes. NDRG2 overexpression aggravated OGD/R‐induced loss of glucose metabolism through reducing glucose uptake, lactate production, NADPH/NADP+ and ATP levels. NDRG2 upregulation exacerbated OGD/R‐caused reduction of glycolysis enzymes (HK2, PKM2 and LDHA) levels. NDRG2 promoted OGD/R‐induced ferroptosis of astrocytes by increasing ROS, iron and PTGS2 levels and decreasing GSH and GPX4 levels. NDRG2 overexpression enhanced OGD/R‐induced decrease of Wnt/β‐catenin signaling activation by reducing Wnt3a and β‐catenin expression. NDRG2 silencing played an opposite effect. Inhibition of Wnt/β‐catenin signaling activation by IWR‐1 attenuated the influences of NDRG2 knockdown on glucose metabolism, glycolysis enzymes levels and ferroptosis. These findings demonstrated that NDRG2 contributes to OGD/R‐induced inhibition of glucose metabolism and promotion of ferroptosis in astrocytes through inhibiting Wnt/β‐catenin signaling activation, which might be associated with ischemic stroke progression.