Differential Mitochondrial Bioenergetics in Neurons and Astrocytes Following Ischemia-Reperfusion Injury and Hypothermia

• Published in: Biomedicines 2024-08, Vol.12 (8), p.1705
• Main Authors: Miyara, Santiago J, Shinozaki, Koichiro, Hayashida, Kei, Shoaib, Muhammad, Choudhary, Rishabh C, Zafeiropoulos, Stefanos, Guevara, Sara, Kim, Junhwan, Molmenti, Ernesto P, Volpe, Bruce T, Becker, Lance B
• Format: Article
• Language: English
• Subjects: Adenosine triphosphate; Analysis; Astrocytes; ATP; Bioenergetics; Brain injury; Cardiac arrest; Care and treatment; Cell culture; Cell lines; Cell viability; Cerebral blood flow; Complications and side effects; Cytotoxicity; Dehydrogenases; Down-regulation; Experiments; Glucose; Glutathione; Heart; Hypothermia; Ischemia; ischemia-reperfusion injury; L-Lactate dehydrogenase; Lipid peroxidation; Lipids; Lysis; Mitochondria; Neuronal-glial interactions; Neurons; Neuroprotection; Oxidation; Reactive oxygen species; Reagents; Reperfusion; Reperfusion injury; Reproducibility; Statistical analysis
• ISSN: 2227-9059; 2227-9059
• DOI: 10.3390/biomedicines12081705

The close interaction between neurons and astrocytes has been extensively studied. However, the specific behavior of these cells after ischemia-reperfusion injury and hypothermia remains poorly characterized. A growing body of evidence suggests that mitochondria function and putative transference between neurons and astrocytes may play a fundamental role in adaptive and homeostatic responses after systemic insults such as cardiac arrest, which highlights the importance of a better understanding of how neurons and astrocytes behave individually in these settings. Brain injury is one of the most important challenges in post-cardiac arrest syndrome, and therapeutic hypothermia remains the single, gold standard treatment for neuroprotection after cardiac arrest. In our study, we modeled ischemia-reperfusion injury by using in vitro enhanced oxygen-glucose deprivation and reperfusion (eOGD-R) and subsequent hypothermia (HPT) (31.5 °C) to cell lines of neurons (HT-22) and astrocytes (C8-D1A) with/without hypothermia. Using cell lysis (LDH; lactate dehydrogenase) as a measure of membrane integrity and cell viability, we found that neurons were more susceptible to eOGD-R when compared with astrocytes. However, they benefited significantly from HPT, while the HPT effect after eOGD-R on astrocytes was negligible. Similarly, eOGD-R caused a more significant reduction in adenosine triphosphate (ATP) in neurons than astrocytes, and the ATP-enhancing effects from HPT were more prominent in neurons than astrocytes. In both neurons and astrocytes, measurement of reactive oxygen species (ROS) revealed higher ROS output following eOGD-R, with a non-significant trend of differential reduction observed in neurons. HPT after eOGD-R effectively downregulated ROS in both cells; however, the effect was significantly more effective in neurons. Lipid peroxidation was higher after eOGD-R in neurons, while in astrocytes, the increase was not statistically significant. Interestingly, HPT had similar effects on the reduction in lipoperoxidation after eOGD-R with both types of cells. While glutathione (GSH) levels were downregulated after eOGD-R in both cells, HPT enhanced GSH in astrocytes, but worsened GSH in neurons. In conclusion, neuron and astrocyte cultures respond differently to eOGD-R and eOGD-R + HTP treatments. Neurons showed higher sensitivity to ischemia-reperfusion insults than astrocytes; however, they benefited more from HPT therapy. These data suggest that given the dif