Increasing NADPH impairs fungal H2O2 resistance by perturbing transcriptional regulation of peroxiredoxin
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ABSTRACT:
SUBMITTER: Li J
PROVIDER: S-EPMC10992141 | biostudies-literature | 2022 Jan
REPOSITORIES: biostudies-literature
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Project description:Reactive oxygen species, such as H2O2, can damage cells but also promote fundamental processes, including growth, differentiation and migration. The mechanisms allowing cells to differentially respond to toxic or signaling H2O2 levels are poorly defined. Here we reveal that increasing external H2O2 produces a bi-phasic response in intracellular H2O2. Peroxiredoxins (Prx) are abundant peroxidases which protect against genome instability, ageing and cancer. We have developed a dynamic model simulating in vivo changes in Prx oxidation. Remarkably, we show that the thioredoxin peroxidase activity of Prx does not provide any significant protection against external rises in H2O2. Instead, our model and experimental data are consistent with low levels of extracellular H2O2 being efficiently buffered by other thioredoxin-dependent activities, including H2O2-reactive cysteines in the thiol-proteome. We show that when extracellular H2O2 levels overwhelm this buffering capacity, the consequent rise in intracellular H2O2 triggers hyperoxidation of Prx to thioredoxin-resistant, peroxidase-inactive form/s. Accordingly, Prx hyperoxidation signals that H2O2 defenses are breached, diverting thioredoxin to repair damage.
| S-EPMC4891068 | biostudies-literature
Project description:Peroxiredoxins are H2O2 scavenging enzymes that also carry out H2O2 signaling and chaperone functions. In yeast, the major cytosolic peroxiredoxin, Tsa1 is required for both promoting resistance to H2O2 and extending lifespan upon caloric restriction. We show here that Tsa1 effects both these functions not by scavenging H2O2, but by repressing the nutrient signaling Ras-cAMP-PKA pathway at the level of the protein kinase A (PKA) enzyme. Tsa1 stimulates sulfenylation of cysteines in the PKA catalytic subunit by H2O2 and a significant proportion of the catalytic subunits are glutathionylated on two cysteine residues. Redox modification of the conserved Cys243 inhibits the phosphorylation of a conserved Thr241 in the kinase activation loop and enzyme activity, and preventing Thr241 phosphorylation can overcome the H2O2 sensitivity of Tsa1-deficient cells. Results support a model of aging where nutrient signaling pathways constitute hubs integrating information from multiple aging-related conduits, including a peroxiredoxin-dependent response to H2O2.
| S-EPMC7392609 | biostudies-literature
Project description:H2O2 can cause oxidative damage associated with age-related diseases such as diabetes and cancer but is also used to initiate diverse responses, including increased antioxidant gene expression. Despite significant interest, H2O2-signaling mechanisms remain poorly understood. Here, we present a mechanism for the propagation of an H2O2 signal that is vital for the adaptation of the model yeast, Schizosaccharomyces pombe, to oxidative stress. Peroxiredoxins are abundant peroxidases with conserved antiaging and anticancer activities. Remarkably, we find that the only essential function for the thioredoxin peroxidase activity of the Prx Tpx1(hPrx1/2) in resistance to H2O2 is to inhibit a conserved thioredoxin family protein Txl1(hTxnl1/TRP32). Thioredoxins regulate many enzymes and signaling proteins. Thus, our discovery that a Prx amplifies an H2O2 signal by driving the oxidation of a thioredoxin-like protein has important implications, both for Prx function in oxidative stress resistance and for responses to H2O2.
| S-EPMC3898613 | biostudies-literature
Project description:Peroxiredoxin 6 (Prdx6) is a bifunctional enzyme with peroxidase activity and Ca2+-independent phospholipase A2 (iPLA2) activity. Here, we report that H2O2-induced cellular toxicity acts through Prdx6 hyperoxidation. Under high concentrations of H2O2 (> 100 microm), Prdx6, and 2-Cys Prdxs were hyperoxidized. Contrary to hyperoxidation of 2-Cys Prdxs, hyperoxidation of Prdx6 was irreversible in vivo. Surprisingly, H2O2-induced cell cycle arrest at the G2/M transition correlated with hyperoxidation and increased iPLA2 activity of Prdx6. This arrest was also associated with up-regulation of p53 and p21 and with down-regulation of cyclin B1. Furthermore, the H2O2-mediated increase in iPLA2 activity was dramatically abolished in a hyperoxidation mutant (C47A), an iPLA2 mutant (S32A), and a double mutant (C47A/S32A) of Prdx6, demonstrating the essential requirement of Prdx6 C47 hyperoxidation for its iPLA2 activity. Together, our results demonstrate that H2O2-mediated hyperoxidation of Prdx6 induces cell cycle arrest at the G2/M transition through up-regulation of iPLA2 activity.
| S-EPMC2662274 | biostudies-literature
Project description:Light controls control a vast array of biological processes, including cell and organelle motility, stress responses, organismal development and the entrainment of circadian rhythms, that maintain diurnal cycles of activity in organisms from cyanobacteria to humans. Recent studies indicate that a type of antioxidant and signaling proteins, peroxiredoxins, sustain circadian rhythms independent of characterized circadian pacemakers in organisms from all the three kingdoms of life, suggesting a role for H2O2 production in circadian clocks. Whereas many circadian clocks involve photosensitive pigments such as melanopsin and cryptochromes it is unclear whether peroxiredoxins can respond to light stimuli and how they interact with global signaling networks regulating e.g. clocks and aging, such as cyclic AMP (cAMP)/protein kinase A (PKA). In yeast, that lacks decidated photoreceptors, blue light induces cAMP-PKA-dependent, nuclear accumulation of a transcription factor, Msn2. However, the mechanism by which light represses pathway activity to stimulate Msn2 nuclear translocation is unknown. Here we identify increased H2O2–production via a conserved peroxisomal oxidase as the cause of light-induced Msn2 nuclear concentration. The H2O2 signal is transduced by the catalytic cysteines of the peroxiredoxin Tsa1 that relieve Msn2 from inhibitory PKA phosphorylation causing its nuclear accumulation. We propose that yeast senses light via H2O2 and a peroxiredoxin to inhibit cAMP/PKA activity and our data form a framework for the study of light responses in cells lacking dedicated light receptors and cAMP-controlled biological rhythms in multicellular organisms.
2018-07-03 | PXD001853 | Pride
Project description:Hydrogen peroxide (H2O2) plays important roles in cellular signalling, yet nonetheless is toxic at higher concentrations. Surprisingly, the mechanism(s) of cellular H2O2 toxicity remain poorly understood. Here, we reveal an important role for mitochondrial 1-Cys peroxiredoxin from budding yeast, Prx1, in regulating H2O2-induced cell death. We show that Prx1 efficiently transfers oxidative equivalents from H2O2 to the mitochondrial glutathione pool. Deletion of PRX1 abrogates glutathione oxidation and leads to a cytosolic adaptive response involving upregulation of the catalase, Ctt1. Both of these effects contribute to improved cell viability following an acute H2O2 challenge. By replacing PRX1 with natural and engineered peroxiredoxin variants, we could predictably induce widely differing matrix glutathione responses to H2O2. Thereby, we demonstrated a key role for matrix glutathione oxidation in driving H2O2-induced cell death. Finally, we reveal that hyperoxidation of Prx1 serves as a switch-off mechanism to limit oxidation of matrix glutathione at high H2O2 concentrations. This enables yeast cells to strike a fine balance between H2O2 removal and limitation of matrix glutathione oxidation.
| S-SCDT-EMBOJ-2019-101552 | biostudies-other
Project description:Fluorescent protein-based reporters used to measure intracellular H2O2 were developed to overcome the limitations of small permeable dyes. The two major families of genetically encoded redox reporters are the reduction-oxidation sensitive green fluorescent protein (roGFP)-based proteins fused to peroxiredoxins and HyPer and derivatives. We have used the most sensitive probes of each family, roGFP2-Tpx1.C169S and HyPer7, to monitor steady-state and fluctuating levels of peroxides in fission yeast. While both are able to monitor the nanomolar fluctuations of intracellular H2O2, the former is two-five times more sensitive than HyPer7, and roGFP2-Tpx1.C169S is partially oxidized in the cytosol of wild-type cells while HyPer7 is fully reduced. We have successfully expressed HyPer7 in the mitochondrial matrix, and it is ~40% oxidized, suggesting higher steady-state levels of peroxides, in the low micromolar range, than in the cytosol. Cytosolic HyPer7 can detect negligible H2O2 in the cytosol from mitochondrial origin unless the main H2O2 scavenger, the cytosolic peroxiredoxin Tpx1, is absent, while mitochondrial HyPer7 is oxidized to the same extent in wild-type and ∆tpx1 cells. We conclude that there is a bidirectional flux of H2O2 across the matrix and the cytosol, but Tpx1 rapidly and efficiently scavenges mitochondrial-generated peroxides and stops their steady-state cytosolic levels rising.
| S-EPMC8148214 | biostudies-literature
Project description:Peroxiredoxins are modulators of aging in yeast and multicellular organisms. The mechanisms by which peroxiredoxins stimulate H2O2 resistance and slow down aging are, however, unclear. Here we show that the yeast peroxiredoxin Tsa1 boosts H2O2 resistance and prevents aging independent of cellular H2O2 levels, but in a manner dependent on H2O2 signaling. More specifically, we pin-point a role of Tsa1 in repressing nutrient signaling via protein kinase A (PKA) that governs both H2O2 resistance and longevity. Tsa1 controls PKA activity at the level of the catalytic subunits and Tpk1 is redox-modified by Tsa1 on a conserved cysteine residue (Cys243) in Tpk1 upon H2O2 addition boosting cellular H2O2 resistance. Tpk1 redox modification dephosphorylates a conserved threonine 241 in the activation loop reducing enzyme activity. We discuss these results in the context of an integrative view on aging where nutrient signaling pathways constitute hubs integrating information from multiple aging-related conduits.
2020-07-27 | PXD012617 | Pride
Project description:Fungal infections cause more than 1.5 million deaths annually. With an increase in immune-deficient susceptible populations and the emergence of antifungal drug resistance, there is an urgent need for novel strategies to combat these life-threatening infections. Here, we use a combinatorial screening approach to identify an imidazopyrazoindole, NPD827, that synergizes with fluconazole against azole-sensitive and -resistant isolates of Candida albicans. NPD827 interacts with sterols, resulting in profound effects on fungal membrane homeostasis and induction of membrane-associated stress responses. The compound impairs virulence in a Caenorhabditis elegans model of candidiasis, blocks C. albicans filamentation in vitro, and prevents biofilm formation in a rat model of catheter infection by C. albicans. Collectively, this work identifies an imidazopyrazoindole scaffold with a non-protein-targeted mode of action that re-sensitizes the leading human fungal pathogen, C. albicans, to azole antifungals.
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Project description:Disulphide formation within the endoplasmic reticulum (ER) requires the activity of the ER oxidase Ero1, and as a consequence, generates hydrogen peroxide. The production of hydrogen peroxide is thought to lead to oxidative stress that ultimately results in apoptosis. Here, we show that mammalian peroxiredoxin IV (PrxIV) metabolises hydrogen peroxide produced by Ero1. We demonstrate that the presence of PrxIV within the ER provides a cytoprotective effect against stresses known to enhance Ero1 activity and perturb ER redox balance. Increased Ero1 activity and production of hydrogen peroxide led to preferential hyperoxidation of PrxIV relative to peroxiredoxins in other cellular compartments. The hyperoxidation was increased by the upregulation of Ero1 and by the expression of a hyperactive Ero1. These findings provide the first evidence for an enzymatic mechanism that facilitates peroxide removal from the ER, and show that the oxidation status of PrxIV acts as a marker for ER oxidative stress.
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