Mitochondrial BKCa Mediates the Protective Effect of Low-Dose Ethanol Preconditioning on Oxygen-Glucose Deprivation and Reperfusion-Induced Neuronal Apoptosis

Abstract

Ischemia-reperfusion (I/R) injury contributes to the morbidity and mortality of ischemic strokes. As an in vitro model, oxygen-glucose deprivation and reperfusion (OGD/R) exposure induces neuronal injury. Low-dose ethanol preconditioning (EtOH-PC) was reported to alleviate neuronal apoptosis during OGD/R. However, whether the mitochondrial BKCa (mitoBKCa) channel is involved in the neuroprotective effect of EtOH-PC during OGD/R is not clearly defined. This study attempts to explore the mediation of the mitoBKCa channel in the neuroprotective effect of EtOH-PC on OGD/R-induced neuronal apoptosis and the underlying mechanisms. OGD/R model was established using primary cortical neurons that were preincubated with ethanol. Subsequently, the cell viability was measured by CCK-8 assay, and the apoptotic cells were determined by TUNEL assay. Annexin V/7-AAD staining and mitochondrial membrane potential using JC-10 were detected by flow cytometry. Western blot analysis was performed to check the apoptosis-related proteins. In the mixed primary culture, 95% neurofilament-positive cells were cortical neurons. Low-dose EtOH-PC (10 mmol/L) for 24 h significantly attenuated the OGD2h/R24h-induced neuronal apoptosis through activating the BKCa channel. Further investigations suggested that ethanol pretreatment increased the mitochondrial membrane potential (MMP) and downregulated the production of cleaved caspase 3 in OGD/R-injured neurons by activating the mitoBKCa channel. Low-dose ethanol pretreatment significantly attenuated the OGD/R-induced neuronal apoptosis mediated by the mitoBKCa channel which modulated the mitochondrial function by impeding the uncontrolled opening of mitochondrial permeability transition pore (MPTP).

NS1619 Alleviate Brain-Derived Extracellular Vesicle-Induced Brain Injury by Regulating BKca Channel and Nrf2/HO-1/NF-ĸB Pathway

“…BKca channel opener can mitigate neuronal depolarization; the elevation of intracellular Ca 2+ and neurotransmitter release after stroke and activation of BKca channel exerts potent neuroprotection [ 50 , 51 ]. Additionally, opening the mitochondrial BKca channel increased the mitochondrial membrane potential and attenuated the oxygen-glucose deprivation and reperfusion-induced upregulated cleaved caspase3 and neuronal apoptosis [ 52 ]. A previous study confirmed that BKca channel opener reduced the production of ROS in isolated rat brain mitochondria.…”

Research hotspots and frontiers of preconditioning in cerebral ischemia: A bibliometric analysis

“…In models of focal cerebral I/R and OGD/R, ischemic preconditioning promoted cell survival by inhibiting I/R-induced reduction of the ER (endoplasmic reticulum)-located calcium sensor STIM1 (stromal interacting molecule 1) and plasma membrane channel ORAI1, blocked by silencing of STIM1 or ORAI1 [ 35 ]. Moderate ethanol preconditioning reduced apoptosis elicited by OGD/R or I/R by elevating the expression of large conductance calcium-activated potassium channels (BK Ca ) [ 137 , 138 ].…”

Para‑hydroxybenzaldehyde against transient focal cerebral ischemia in rats via mitochondrial preservation

“…MPTP reflects the structure and function of the mitochondria and it is located between the inner and outer membranes of the organelle (65). The lipid oxidative stress damage to the mitochondrial membrane leads to the abnormal opening of MPTP, which cannot maintain the normal potential difference of the inner membrane, while the oxidative phosphorylation on the inner membrane cannot proceed smoothly (66,67). The cytochrome C oxidase is also known as respiratory chain complex IV and it is embedded in the bilayer lipid membrane of the inner mitochondrial membrane (68).…”