Oxidant-Induced Cell Death in Respiratory Epithelial Cells Is Due to Dna Damage and Loss of Atp

Abstract

Oxidative stress is considered to be an important pathogenic event in ischemia-reperfusion injury, leading to apoptosis or necrosis. We show acute cytotoxicity upon exposure to hydrogen peroxide (H(2)O(2)) in BEAS-2B cells and A549 cells. Single-cell gel electrophoresis showed formation of large comet tails from DNA upon oxidant exposure suggestive of DNA damage. The ATP content of the cells decreased upon exposure to H(2)O(2). Preincubation with 3-aminobenzamide (3-ABA), an inhibitor of poly (ADP-ribosyl) polymerase (PARP), prevented the cytotoxicity. The decrease in the ATP content of the cells was also prevented by 3-ABA. Increase in PARP activity was further confirmed by measuring incorporation of [(32)P]-NAD into nuclear proteins in presence of the cell extracts. Markers of apoptosis were not seen in cells treated with H(2)O(2) with or without 3-ABA pretreatment. These studies suggest that DNA damage is one of the primary reasons for oxidant-induced cell death and that PARP plays an important role in cell death due to its consumption of ATP. Further elaboration of this and other pathways that consume ATP may help prevent oxidant-mediated acute lung injury.

Reductive activation of hexavalent chromium by human lung epithelial cells: Generation of Cr(V) and Cr(V)-thiol species

“…Since these spectra were run on frozen samples, the signal was seen at g = 1.987 which is equivalent to a g = 1.996 signal at room temperature where g iso = ⅓[2.014 + 2(1.987)]. However, these A549 cells are different in many ways from BEAS-2B in that A549 cells: (a) are not normal epithelial cells, but rather a hypotriploid lung adenocarcinoma [74]; (b) consist of at least 4 different cell types [75]; and (c) are 10-fold more resistant to H 2 O 2 than are BEAS-2B cells [76]. Given these marked differences, the differences in Cr(V) spectra are not surprising.…”

Biochemical and neurochemical sequelae following mild traumatic brain injury: summary of experimental data and clinical implications

“…Independent of the predominant mechanism, the final result is certainly deleterious for the correct functioning of cell metabolism. Finally, the augmentation of poly-ADP ribosylation reactions through the activation of the enzyme poly-ADP ribose polymerase 22,58,61 has been demonstrated to trigger the mechanisms of apoptotic induction. 95 The fact that NAA, ATP, MDA, ascorbate, oxipurines, nucleosides, and nicotinic coenzymes spontaneously recovered in mTBI and after hypoxia and hypotension alone seemed to suggest that there is a threshold for mitochondrial dysfunction beyond which restoration of neurochemical physiology is prevented.…”

“…66,97 As suggested by experiments in which the mitochondrial capacity to catalyze the tetravalent reduction of molecular oxygen through the electron transport chain appears compromised, dysfunctional mitochondria seem to be the main intracellular source of ROS production. 58,60,61,73 However, in conjunction with oxidative stress, we also studied the importance of another event occurring as a consequence of TBI, a phenomenon known as nitrosative stress. Only more recently the object of substantial investigations, nitrosative stress is defined as an overproduction of reactive nitrogen species (RNS) through the Ca 2+ -dependent activation of neuronal nitric oxide (NO) synthase and of the increased synthesis of the inducible form of NO synthase, generally taking place in concomitance with oxidative stress.…”

Hydrogen Peroxide Induces Topoisomerase I-mediated DNA Damage and Cell Death

“…Apoptosis Induced by Hydrogen Peroxide Is Reduced in TOP1-deficient Cells-Hydrogen peroxide is known to induce both necrosis and apoptosis (48,49). We have investigated the role of TOP1 in hydrogen peroxide-induced apoptosis by assaying two apoptotic endpoints, nucleosomal DNA fragmentation, and caspase activation.…”