Identification of conoidin A as a covalent inhibitor of peroxiredoxin II

Haraldsen, Jeralyn D.; Gu, Lin; Botting, Catherine H.; Walton, Jeffrey G. A.; Storm, Janet; Phalen, Timothy; Kwok, Lai Yu; Soldati‐Favre, Dominique; Heintz, Nicholas H.; Müller, Sylke; Westwood, Nicholas J.; Ward, Gary E.

doi:10.1039/b901735f

Cited by 68 publications

(65 citation statements)

References 30 publications

(58 reference statements)

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“…Cells were then collected and washed in preparation for analysis of cell death and mitochondrial membrane potential. Where the effects of thioredoxin antioxidant system inhibitors on photodynamic cell killing were tested, cells were co-treated with 1 mM MAL in the absence or presence of non-toxic concentrations of each inhibitor, which consisted of: auranofin (Enzo Life Sciences), a thioredoxin reductase 1 and 2 chemical inhibitor [22];PX-12 (2-[(1-methylpropyl)dithio]-1H-imidazole; Tocris Bioscience), an irreversible selective thioredoxin-1 inhibitor [23]; thioredoxin-1 inhibitors PMX290 (4-(1-benzenesulfonyl-6-fluoro1Hindol-2-yl)-4-hydroxy-cyclohexa-2,5-dienone; Abcam) [24,25] and PMX464 (4-(2-benzothiazolyl)-4-hydroxy-2,5-cyclohexadien-1-one; Tocris) [25,26] and conoidin A (Cayman Chemicals), a peroxiredoxin 1 and 2 inactivator [27]. Flow cytometry was carried out using Beckman Coulter Quanta SC and Merck Guava® easyCyte flow cytometers.…”

Section: Photodynamic Treatmentsmentioning

confidence: 99%

Altered cellular redox homeostasis and redox responses under standard oxygen cell culture conditions versus physioxia

Ferguson

Smerdon

Harries

et al. 2018

Free Radical Biology and Medicine

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In vivo, mammalian cells reside in an environment of 0.5-10% O 2 (depending on the tissue location within the body), whilst standard in vitro cell culture is carried out under room air. Little is known about the effects of this hyperoxic environment on treatment-induced oxidative stress, relative to a physiological oxygen environment. In the present study we investigated the effects of long-term culture under hyperoxia (air) on photodynamic treatment. Upon photodynamic irradiation, cells which had been cultured long-term under hyperoxia generated higher concentrations of mitochondrial reactive oxygen species, compared with cells in a physioxic (2% O 2 ) environment. However, there was no significant difference in viability between hyperoxic and physioxic cells. The expression of genes encoding key redox homeostasis proteins and the activity of key antioxidant enzymes was significantly higher after the long-term culture of hyperoxic cells compared with physioxic cells. The induction of antioxidant genes and increased antioxidant enzyme activity appear to contribute to the development of a phenotype that is resistant to oxidative stress-induced cellular damage and death when using standard cell culture conditions. The results from experiments using selective inhibitors suggested that the thioredoxin antioxidant system contributes to this phenotype. To avoid artefactual results, in vitro cellular responses should be studied in mammalian cells that have been cultured under physioxia. This investigation provides new insights into the effects of physioxic cell culture on a model of a clinically relevant photodynamic treatment and the associated cellular pathways.

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Section: Photodynamic Treatmentsmentioning

confidence: 99%

Altered cellular redox homeostasis and redox responses under standard oxygen cell culture conditions versus physioxia

Ferguson

Smerdon

Harries

et al. 2018

Free Radical Biology and Medicine

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“…3 A). We used conoidin A (Con A) to covalently inactivate peroxiredoxins (Prx), which are highly abundant and reactive, cytoplasmic H 2 O 2 scavengers (29). We also inhibited regeneration of reduced thioredoxin (Trx) by blocking thioredoxin reductase with auranofin (Aur) (30).…”

Section: The Peroxiredoxin-thioredoxin Antioxidant Chain Limits H 2 Omentioning

confidence: 99%

Image-Based Measurement of H 2 O 2 Reaction-Diffusion in Wounded Zebrafish Larvae

Jelcic

Enyedi

Xavier

et al. 2017

Biophysical Journal

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Epithelial injury induces rapid recruitment of antimicrobial leukocytes to the wound site. In zebrafish larvae, activation of the epithelial NADPH oxidase Duox at the wound margin is required early during this response. Before injury, leukocytes are near the vascular region, that is, $100-300 mm away from the injury site. How Duox establishes long-range signaling to leukocytes is unclear. We conceived that extracellular hydrogen peroxide (H 2 O 2 ) generated by Duox diffuses through the tissue to directly regulate chemotactic signaling in these cells. But before it can oxidize cellular proteins, H 2 O 2 must get past the antioxidant barriers that protect the cellular proteome. To test whether, or on which length scales this occurs during physiological wound signaling, we developed a computational method based on reaction-diffusion principles that infers H 2 O 2 degradation rates from intravital H 2 O 2 -biosensor imaging data. Our results indicate that at high tissue H 2 O 2 levels the peroxiredoxin-thioredoxin antioxidant chain becomes overwhelmed, and H 2 O 2 degradation stalls or ceases. Although the wound H 2 O 2 gradient reaches deep into the tissue, it likely overcomes antioxidant barriers only within $30 mm of the wound margin. Thus, Duox-mediated long-range signaling may require other spatial relay mechanisms besides extracellular H 2 O 2 diffusion.

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“…[2] 1 targets TgPrxII both in vitro and in live parasites and also inhibits the hyperoxidation of two mammalian peroxiredoxin homologues (PrxI and PrxII) in cells. [2] As the biology and chemistry associated with mammalian peroxiredoxins has entered a new phase, with the discovery that these proteins are involved in complex intracellular signalling cascades and are overexpressed in several cancers, inhibitors of peroxiredoxins are of increasing interest. [3,4] To date, there are only a few examples of Prx inhibitors in general [5] and the Toxoplasma enzyme TgPrxII in particular.…”

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confidence: 99%