Cellular knock-down of quinone reductase 2: A laborious road to successful inhibition by RNA interference

Chomarat, Pascale; Cogé, Francis; Guénin, Sophie P.; Mailliet, François; Vella, F; Mallet, Catherine; Giraudet, Stephanie; Nagel, Nadine; Léonce, Stéphane; Ferry, Gilles; Delagrange, Philippe; Boutin, Jean A.

doi:10.1016/j.biochi.2007.07.004

Cited by 16 publications

(16 citation statements)

References 59 publications

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“…This is likely attributable to two independent factors, namely the induction of the protein and the availability of NRH. QR2 activity leads to hydroquinone and semi-quinone, the latter being a deleterious species for the cell (Chomarat et al, 2007). Its activity is also accompanied by increased production of ROS deleterious for the cell (Gong et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Loss of Quinone Reductase 2 Function Selectively Facilitates Learning Behaviors

Benoit¹,

Bastianetto²,

Brouillette³

et al. 2010

J. Neurosci.

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High levels of reactive oxygen species (ROS) are associated with deficits in learning and memory with age as well as in Alzheimer's disease. Using DNA microarray, we demonstrated the overexpression of quinone reductase 2 (QR2) in the hippocampus in two models of learning deficits, namely the aged memory impaired rats and the scopolamine-induced amnesia model. QR2 is a cytosolic flavoprotein that catalyzes the reduction of its substrate and enhances the production of damaging activated quinone and ROS. QR2-like immunostaining is enriched in cerebral structures associated with learning behaviors, such as the hippocampal formation and the temporofrontal cortex of rat, mouse, and human brains. In cultured rat embryonic hippocampal neurons, selective inhibitors of QR2, namely S26695 and S29434, protected against menadione-induced cell death by reversing its proapoptotic action. S26695 (8 mg/kg) also significantly inhibited scopolamine-induced amnesia. Interestingly, adult QR2 knock-out mice demonstrated enhanced learning abilities in various tasks, including Morris water maze, object recognition, and rotarod performance test. Other behaviors related to anxiety (elevated plus maze), depression (forced swim), and schizophrenia (prepulse inhibition) were not affected in QR2-deficient mice. Together, these data suggest a role for QR2 in cognitive behaviors with QR2 inhibitors possibly representing a novel therapeutic strategy toward the treatment of learning deficits especially observed in the aged brain.

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Section: Discussionmentioning

confidence: 99%

Loss of Quinone Reductase 2 Function Selectively Facilitates Learning Behaviors

Benoit¹,

Bastianetto²,

Brouillette³

et al. 2010

J. Neurosci.

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“…In contrast to QR1, QR2 was originally discovered in the 1960s but has not been as widely studied as QR1 due to its obscured identification as NQO2, the current name of another, mitochondrial membrane‐bound enzyme also known as complex I 2. However, interest in QR2 underwent a resurgence in the 1990's and has gained attention in a myriad of biological fields for its proposed roles in malaria, cancer, neurological degenerative diseases, memory and, more generally, oxidative stress 3–10. Initially, renewed interest in QR2 was strongly linked to its ability to utilize a rather rare form of hydride donors ( N ‐methyl or N ‐ribosyl nicotinamide) instead of the classical NAD(P)H donors, a situation contrary to that of QR1 10.…”

Section: Introductionmentioning

confidence: 99%

“…Initially, renewed interest in QR2 was strongly linked to its ability to utilize a rather rare form of hydride donors ( N ‐methyl or N ‐ribosyl nicotinamide) instead of the classical NAD(P)H donors, a situation contrary to that of QR1 10. QR2 has also been proposed to generate free radical quinones since the QR2 genetic knock‐outs in some living systems are less sensitive to quinone toxicity in contrast to QR1, which deactivates quinones through a two electron reduction 4, 11, 12. Beyond QR2 activation of quinones, it has also been implicated in the so‐called French paradox due to its nanomolar affinity for resveratrol, a well known cancer preventive agent 11.…”

Section: Introductionmentioning

confidence: 99%

X‐ray structural studies of quinone reductase 2 nanomolar range inhibitors

et al. 2011

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Quinone reductase 2 (QR2) is one of two members comprising the mammalian quinone reductase family of enzymes responsible for performing FAD mediated reductions of quinone substrates. In contrast to quinone reductase 1 (QR1) which uses NAD(P)H as its co-substrate, QR2 utilizes a rare group of hydride donors, N-methyl or N-ribosyl nicotinamide. Several studies have linked QR2 to the generation of quinone free radicals, several neuronal degenerative diseases, and cancer. QR2 has been also identified as the third melatonin receptor (MT3) through in cellulo and in vitro inhibition of QR2 by traditional MT3 ligands, and through recent X-ray structures of human QR2 (hQR2) in complex with melatonin and 2-iodomelatonin. Several MT3 specific ligands have been developed that exhibit both potent in cellulo inhibition of hQR2 nanomolar, affinity for MT3. The potency of these ligands suggest their use as molecular probes for hQR2. However, no definitive correlation between traditionally obtained MT3 ligand affinity and hQR2 inhibition exists limiting our understanding of how these ligands are accommodated in the hQR2 active site. To obtain a clearer relationship between the structures of developed MT3 ligands and their inhibitory properties, in cellulo and in vitro IC 50 values were determined for a representative set of MT3 ligands (MCA-NAT, 2-I-MCANAT, prazosin, S26695, S32797, and S29434). Furthermore, X-ray structures for each of these ligands in complex with hQR2 were determined allowing for a structural evaluation of the binding modes of these ligands in relation to the potency of MT3 ligands.

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“…Mice that have been fed resveratrol have been shown to be less sensitive to menadione-induced toxicity compared with control mice, and this observation parallels the observation that QR2 −/− mice are also less sensitive to menadione-induced toxicity compared with their wild-type littermates. The toxicity of menadione in the wild-type animals has been shown to increase upon co-administration of a QR2 co-substrate [13], and cells derived from QR2 −/− animals or QR2-RNAi (RNA interference) knockdown cells have been shown to be less sensitive to menadione toxicity [12,14]. …”

Section: Introductionmentioning

confidence: 99%

Kinetic, thermodynamic and X-ray structural insights into the interaction of melatonin and analogues with quinone reductase 2

Calamini

Santarsiero

Boutin

et al. 2008

Biochemical Journal

128

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Melatonin exerts its biological effects through at least two transmembrane G-protein-coupled receptors, MT1 and MT2, and a lower-affinity cytosolic binding site, designated MT3. MT3 has recently been identified as QR2 (quinone reductase 2) (EC 1.10.99.2) which is of significance since it links the antioxidant effects of melatonin to a mechanism of action. Initially, QR2 was believed to function analogously to QR1 in protecting cells from highly reactive quinones. However, recent studies indicate that QR2 may actually transform certain quinone substrates into more highly reactive compounds capable of causing cellular damage. Therefore it is hypothesized that inhibition of QR2 in certain cases may lead to protection of cells against these highly reactive species. Since melatonin is known to inhibit QR2 activity, but its binding site and mode of inhibition are not known, we determined the mechanism of inhibition of QR2 by melatonin and a series of melatonin and 5-hydroxytryptamine (serotonin) analogues, and we determined the X-ray structures of melatonin and 2-iodomelatonin in complex with QR2 to between 1.5 and 1.8 Å (1 Å =0.1 nm) resolution. Finally, the thermodynamic binding constants for melatonin and 2-iodomelatonin were determined by ITC (isothermal titration calorimetry). The kinetic results indicate that melatonin is a competitive inhibitor against N-methyldihydronicotinamide (Ki = 7.2 μM) and uncompetitive against menadione (Ki = 92 μM), and the X-ray structures shows that melatonin binds in multiple orientations within the active sites of the QR2 dimer as opposed to an allosteric site. These results provide new insights into the binding mechanisms of melatonin and analogues to QR2.

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Cellular knock-down of quinone reductase 2: A laborious road to successful inhibition by RNA interference

Cited by 16 publications

References 59 publications

Loss of Quinone Reductase 2 Function Selectively Facilitates Learning Behaviors

Loss of Quinone Reductase 2 Function Selectively Facilitates Learning Behaviors

X‐ray structural studies of quinone reductase 2 nanomolar range inhibitors

Kinetic, thermodynamic and X-ray structural insights into the interaction of melatonin and analogues with quinone reductase 2

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