Assessing Bioenergetic Function in Response to Reactive Oxygen Species in Neural Cells

Abstract

In this study, we characterized the bioenergetic response of the Lund human mesencephalic (LUHMES) cell line and a mouse astrocyte cell line to oxidative stress. Extracellular hydrogen peroxide (H2O2) levels and bioenergetic response were investigated in these cell lines after exposure to paraquat (PQ), a redox cycling compound that causes oxidative stress in cells. We used extracellular flux analysis to measure mitochondrial function in adherent astrocytes and LUHMES cells. Extracellular H2O2 was measured fluorometrically. H2O2 levels increased in both cell lines after exposure to 5 µM PQ for 18 h; however, the extent of H2O2 increase with astrocytes was significantly lower than that with LUHMES cells (33% vs. 67%). Measurements of basal mitochondrial respiration showed that PQ almost completely eliminated oxygen consumption rate (OCR) in astrocytes and significantly reduced it in LUHMES cells. Notably, OCR in LUHMES cells was higher than that in astrocytes, indicating that neuronal cells maintain higher oxidative metabolism than glial cells, which is also consistent with higher energy demands of the neuronal cells. Moreover, LUHMES cells exhibited a higher amount of adenosine triphosphate (ATP) being produced by oxidative phosphorylation than by glycolysis. In contrast, astrocytes demonstrated a higher glycolytic capacity and glycolytic reserve than LUHMES cells and higher ATP production rate by glycolysis than its production by mitochondrial oxidative metabolism. Collectively, this study showed the differential bioenergetic responses between astrocytes and LUHMES cells in responding to oxidative stress and the findings may provide insights into the mitochondrial reserve capacity in neurons and astrocytes in responding to oxidative stress. (First online: Mar 30, 2021)

Modulation of Pyruvate Export and Extracellular Pyruvate Concentration in Primary Astrocyte Cultures

“…For peripheral cell lines, the detectable extracellular pyruvate level has been reported to be lowered to some extent by such a reaction [ 53 ]. As the release of small amounts of hydrogen peroxide has been reported for an astroglial cell line [ 54 ] as well as for cultured primary and secondary astrocytes [ 55 – 57 ], we tested whether extracellular oxidation of pyruvate by cell-generated extracellular hydrogen peroxide may also lower the detectable extracellular pyruvate concentration in astrocyte cultures. The cells were incubated for 5 h with 5 mM glucose without or with 1 mM pyruvate in the absence or the presence of catalase and/or superoxide dismutase (SOD) to efficiently remove extracellular superoxide and hydrogen peroxide during the incubation, as previously shown for cultured astrocytes [ 58 , 59 ].…”

Establishing an Oxidative Stress Model in the Human Mesencephalic Cell Line (LUHMES): an in vitro study

“…In the literature various in vitro cell culture models were created using hydrogen peroxide. Sameti et al investigated the effect of hydrogen peroxide on bioenergetic mechanism in astrocytes and LUHMES cell line [34]; in another study, they investigated the effect of hydrogen peroxide directly on DNA damage [35]. Schlachetzki et al examined the effects of hydrogen peroxide on neurodegenerative diseases in cell culture models [36].…”

Quantum Neurobiology

“…Applying differential geometry to empirical TEM tomography data, however, allows a more robust analytic model based on Gaussian curvature, surface area, volume, and membrane motifs, all of which are related to the metabolic output of the mitochondria and require a multi-dimensional approach. Such differential geometry methods might inflect into practical applications treating mitochondrial bioenergetic stress response [157].…”