Antioxidant cytoprotection by peroxisomal peroxiredoxin-5

Abstract

Peroxiredoxin-5 (PRDX5) is a thioredoxin peroxidase that reduces hydrogen peroxide, alkyl hydroperoxides, and peroxynitrite. This enzyme is present in the cytosol, mitochondria, peroxisomes, and nucleus in human cells. Antioxidant cytoprotective functions have been previously documented for cytosolic, mitochondrial, and nuclear mammalian PRDX5. However, the exact function of PRDX5 in peroxisomes is still not clear. The aim of this work was to determine the function of peroxisomal PRDX5 in mammalian cells and, more specifically, in glial cells. To study the role of PRDX5 in peroxisomes, the endogenous expression of PRDX5 in murine oligodendrocyte 158N cells was silenced by RNA interference. In addition, human PRDX5 was also overexpressed in peroxisomes using a vector coding for human PRDX5, whose unconventional peroxisomal targeting sequence 1 (PTS1; SQL) was replaced by the prototypical PTS1 SKL. Stable 158N clones were obtained. The antioxidant cytoprotective function of peroxisomal PRDX5 against peroxisomal and mitochondrial KillerRed-mediated reactive oxygen species production as well as H2O2 was examined using MTT viability assays, roGFP2, and C11-BOBIPY probes. Altogether our results show that peroxisomal PRDX5 protects 158N oligodendrocytes against peroxisomal and mitochondrial KillerRed- and H2O2-induced oxidative stress.

ROS production induced by BRAF inhibitor treatment rewires metabolic processes affecting cell growth of melanoma cells

“…The plasmid encoding the cytosolic (cyto)-human glutaredoxin 1 (Grx1)-roGFP2 was obtained by amplifying the cDNA Grx1-roGFP2 sequence without the Peroxisomal Targeting Sequence 1 (PTS1) from the plasmid encoding the peroxisomal (po)-Grx1-roGFP2 vector [19] by PCR (primers; pCyto-EcoRI-5′ 5′-gga gga gga tca gga gga gaa ttc gtg agc aag ggc gag gag-3′ (forward) and pCyto-XbaI-3′ 5′-ctc gac tta tct aga tta ctt gta cag ctc gtc-3′ (reverse)) and subcloned into PCR2.1-TOPO (Invitrogen). The resulting plasmid was digested with EcoRI and XbaI, prior to subcloning into the EcoRI/XbaI digested pcDNA3.1-Grx1-roGFP2-PTS1 vector to obtain the p-cyto-Grx1-roGFP2.…”

The Peroxisome-Mitochondria Connection: How and Why?

“…Finally, targeted variants of KillerRed, a red fluorescent photosensitizer that efficiently generates O 2 •− upon green light illumination [131], have been employed to study redox communication between peroxisomes and mitochondria in mammalian cells [108,132,133]. On one hand, these studies confirmed and extended the concept that mitochondrial redox balance is quickly perturbed upon generation of excess ROS inside peroxisomes.…”

“…On one hand, these studies confirmed and extended the concept that mitochondrial redox balance is quickly perturbed upon generation of excess ROS inside peroxisomes. On the other hand, they provided the first evidence that (i) peroxisomes largely resist oxidative stress when the burden originates within mitochondria [108]; and (ii) redox communication between peroxisomes and mitochondria involves complex signaling pathways [132,133]. Importantly, although the identity and mechanisms of these pathways remain to be elucidated (and may differ according to the type and amount of ROS produced), the data presented in this section strongly support the idea that mitochondria may act as dynamic receivers, integrators, and transmitters of peroxisome-derived mediators of oxidative stress [132].…”

Molecular Mechanisms and Physiological Significance of Organelle Interactions and Cooperation

“…As already mentioned above, SOD1 can convert O (Knoops et al, 2011). GSTK1 and MGST1 are thought to play a role in LOOH detoxification processes Johansson et al, 2010;Wang et al, 2013b), EPHX2 can convert epoxides to the corresponding dihydrodiols (Decker et al, 2009), and peroxisomal PRDX5 has recently been shown to exert a cytoprotective function against H 2 O 2 -and LOOH-induced oxidative stress (Walbrecq et al, 2015). For a detailed description of these enzymes, the reader is referred to other reviews .…”