Overexpression of Mitochondrial Methionine Sulfoxide Reductase B2 Protects Leukemia Cells from Oxidative Stress-induced Cell Death and Protein Damage

Abstract

According to the mitochondrial theory of aging, mitochondrial dysfunction increases intracellular reactive oxidative species production, leading to the oxidation of macromolecules and ultimately to cell death. In this study, we investigated the role of the mitochondrial methionine sulfoxide reductase B2 in the protection against oxidative stress. We report, for the first time, that overexpression of methionine sulfoxide reductase B2 in mitochondria of acute T-lymphoblastic leukemia MOLT-4 cell line, in which methionine sulfoxide reductase A is missing, markedly protects against hydrogen peroxide-induced oxidative stress by scavenging reactive oxygen species. The addition of hydrogen peroxide provoked a time-gradual increase of intracellular reactive oxygen species, leading to a loss in mitochondrial membrane potential and to protein carbonyl accumulation, whereas in methionine sulfoxide reductase B2-overexpressing cells, intracellular reactive oxygen species and protein oxidation remained low with the mitochondrial membrane potential highly maintained. Moreover, in these cells, delayed apoptosis was shown by a decrease in the cleavage of the apoptotic marker poly(ADP-ribose) polymerase-1 and by the lower percentage of Annexin-V-positive cells in the late and early apoptotic stages. We also provide evidence for the protective mechanism of methionine sulfoxide reductase B2 against protein oxidative damages. Our results emphasize that upon oxidative stress, the overexpression of methionine sulfoxide reductase B2 leads to the preservation of mitochondrial integrity by decreasing the intracellular reactive oxygen species build-up through its scavenging role, hence contributing to cell survival and protein maintenance.

Dimethyl sulfoxide elevates hydrogen peroxide-mediated cell death in Saccharomyces cerevisiae by inhibiting the antioxidant function of methionine sulfoxide reductase A

“…Deletion or knockdown of MsrA and MsrB genes in organisms ranging from bacteria to mammals results in increased sensitivity to oxidative stress (17,(19)(20)(21)(22)(23). Conversely, overexpression of these genes protects against oxidative stress-induced cell death (24)(25)(26)(27). In addition, fRMsr also has an antioxidant function in yeast (15).…”

Dual Sites of Protein Initiation Control the Localization and Myristoylation of Methionine Sulfoxide Reductase A

“…Several investigations demonstrated that modulation of MsrA activity altered the level of reactive oxygen species; overexpression lowered the level in PC-12 cells (13), whereas lens cells lacking MsrA had an increased level (14). Increased expression of either MsrA in WI-38 fibroblasts or MsrB in MOLT-4 leukemia cells reduced the steady state level of oxidized proteins after a hydrogen peroxide challenge (15,16).Accumulation of oxidatively damaged proteins has been hypothesized to be an important mechanism of the aging process (17), and it is notable that overexpression of MsrA in Drosophila doubled the life span of the flies (10). We wished to determine whether the life extension observed in flies would also occur in mammals overexpressing MsrA and, if it did, whether the subcellular localization of MsrA were important.…”

“…Several investigations demonstrated that modulation of MsrA activity altered the level of reactive oxygen species; overexpression lowered the level in PC-12 cells (13), whereas lens cells lacking MsrA had an increased level (14). Increased expression of either MsrA in WI-38 fibroblasts or MsrB in MOLT-4 leukemia cells reduced the steady state level of oxidized proteins after a hydrogen peroxide challenge (15,16).…”

Biomarkers of protein oxidation from a chemical, biological and medical point of view

“…It has to be mentioned that the described modifications are mainly due to the action of ROS and that a large number of further amino acid derivates might also be formed by the action of reactive species derived from nitrogen monoxide or hypochloric acid (for details see Voss and Grune, 2006). proteins that accumulate upon oxidative stress by maintaining a low level of intracellular ROS (Cabreiro et al, 2008).…”