Biochemical and behavioural characterization of EMPA, a novel high‐affinity, selective antagonist for the OX<sub>2</sub> receptor

Malherbe, Pari; Borroni, Edilio; Gobbi, Luca; Knust, Henner; Nettekoven, Matthias; Pinard, Emmanuel; Roche, Olivier; Rogers‐Evans, Mark; Wettstein, JG; Jl, Moreau

doi:10.1111/j.1476-5381.2009.00127.x

Cited by 88 publications

(94 citation statements)

References 49 publications

(109 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The pA 2 and Schild slope values of EMPA are 7.4 and 1.1, respectively. Given that EMPA and suvorexant bind to the OX2R with high affinity and antagonize orexininduced transient increase in intracellular Ca 2+ concentration through a competitive mechanism (20), these results show that YNT-185 acts as an orthosteric, full agonist for OX2R. These results are consistent with our previous report, which indicated that YNT-185 displaced [ 125 I] orexin-A binding to OX2R in a dose-dependent manner (19).…”

Section: Resultssupporting

confidence: 83%

Nonpeptide orexin type-2 receptor agonist ameliorates narcolepsy-cataplexy symptoms in mouse models

Irukayama-Tomobe

Ogawa

Tominaga

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

112

View full text Add to dashboard Cite

Narcolepsy-cataplexy is a debilitating disorder of sleep/wakefulness caused by a loss of orexin-producing neurons in the lateroposterior hypothalamus. Genetic or pharmacologic orexin replacement ameliorates symptoms in mouse models of narcolepsy-cataplexy. We have recently discovered a potent, nonpeptide OX2R-selective agonist, YNT-185. This study validates the pharmacological activity of this compound in OX2R-transfected cells and in OX2R-expressing neurons in brain slice preparations. Intraperitoneal, and intracerebroventricular, administration of YNT-185 suppressed cataplexy-like episodes in orexin knockout and orexin neuron-ablated mice, but not in orexin receptor-deficient mice. Peripherally administered YNT-185 also promotes wakefulness without affecting body temperature in wild-type mice. Further, there was no immediate rebound sleep after YNT-185 administration in active phase in wild-type and orexindeficient mice. No desensitization was observed after repeated administration of YNT-185 with respect to the suppression of cataplexy-like episodes. These results provide a proof-of-concept for a mechanistic therapy of narcolepsy-cataplexy by OX2R agonists. neuropeptides produced by neurons exclusively localized to the lateral hypothalamus that act on two G protein-coupled receptors termed OX1R and OX2R (1). Orexin-producing neurons send axons diffusely through the central nervous system, with especially dense innervations to several nuclei involved in sleep/wakefulness regulation (2, 3). Because orexins have been implicated in the maintenance of wakefulness, many groups are trying to develop nonpeptidic orexin receptor antagonists aiming at new medication for insomnia. Recently, suvorexant, a dual orexin receptor antagonist, was clinically approved in Japan and the United States (4, 5).A crucial role of the orexin system in the regulation of sleep/ wakefulness was initially uncovered by the discovery that OX2R-deficient dogs (6) and prepro-orexin knockout (Hcrt −/− , abbreviated as OXKO) mice (2) exhibited symptoms resembling human narcolepsy-cataplexy. According to the clinical definition by the International Classification of Sleep Disorders-Third Edition, two types of narcoleptic disorders are categorized (7). Narcolepsy type 1 is characterized by the existence of cataplexy and low levels of orexin-A in cerebrospinal fluid (CSF) (8-10). However, patients with narcolepsy type 2 show no cataplexy and normal orexin-A levels in CSF. Narcolepsy-cataplexy, or narcolepsy type 1 (11), is characterized by a marked instability of sleep/ wake state transitions, resulting in nonrapid eye movement (NREM) sleep-related symptoms (e.g., excessive daytime sleepiness, "sleep attacks," and fragmented nighttime sleep), and rapid eye movement (REM) sleep-related symptoms (e.g., cataplexy, sleep paralysis, and hypnagogic/hypnopompic hallucinations). In polysomnography, narcolepsy-cataplexy patients show markedly reduced daytime sleep latency, and sleep-onset REM periods (SOREMs). Currently available treatments for narcolepsyca...

show abstract

Section: Resultssupporting

confidence: 83%

Nonpeptide orexin type-2 receptor agonist ameliorates narcolepsy-cataplexy symptoms in mouse models

Irukayama-Tomobe

Ogawa

Tominaga

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

112

View full text Add to dashboard Cite

show abstract

“…To map the distribution/reactivation of OX2R, we conducted receptor autoradiography by using [ 3 H]-labeled EMPA, a highly selective OX2R antagonist (16). We microinjected OX2R TD mice with AAV-Cre (n = 3) or AAV-GFP (n = 2) and used WT mice (n = 2) as normal controls.…”

Section: Methodsmentioning

confidence: 99%

“…4A). In some mice, we mapped the expression of OX2R by using the highly selective OX2R antagonist N-ethyl-2-[(6-methoxy-pyridin-3-yl)-(toluene-2-sulfonyl)-amino]-N-pyridin-3-ylmethyl-acetamide (EMPA) (16). In WT mice, [ 3 H]EMPA labeled neurons in a pattern very similar to that reported for Hcrtr2 (Ox2r) mRNA (4), but in OX2R TD mice injected with AAV-Cre, [ 3 H]EMPA labeling was limited to just the TMN and adjacent SuM (Fig.…”

Section: Focal Rescue Of Ox2r Signaling In Tmn Region Improves Fragmementioning

confidence: 99%

Orexin receptor 2 expression in the posterior hypothalamus rescues sleepiness in narcoleptic mice

Mochizuki¹,

Arrigoni²,

Marcus

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

122

View full text Add to dashboard Cite

Narcolepsy is caused by a loss of orexin/hypocretin signaling, resulting in chronic sleepiness, fragmented non-rapid eye movement sleep, and cataplexy. To identify the neuronal circuits underlying narcolepsy, we produced a mouse model in which a loxP-flanked gene cassette disrupts production of the orexin receptor type 2 (OX2R; also known as HCRTR2), but normal OX2R expression can be restored by Cre recombinase. Mice lacking OX2R signaling had poor maintenance of wakefulness indicative of sleepiness and fragmented sleep and lacked any electrophysiological response to orexin-A in the wake-promoting neurons of the tuberomammillary nucleus. These defects were completely recovered by crossing them with mice that express Cre in the female germline, thus globally deleting the transcription-disrupter cassette. Then, by using an adeno-associated viral vector coding for Cre recombinase, we found that focal restoration of OX2R in neurons of the tuberomammillary nucleus and adjacent parts of the posterior hypothalamus completely rescued the sleepiness of these mice, but their fragmented sleep was unimproved. These observations demonstrate that the tuberomammillary region plays an essential role in the wakepromoting effects of orexins, but orexins must stabilize sleep through other targets.arcolepsy is caused by a selective loss of the hypothalamic neurons producing the orexin (i.e., hypocretin) neuropeptides and is one of the most common causes of chronic sleepiness (1). In humans and mice, loss of orexin signaling results in unstable sleep/wake states, with poor maintenance of wakefulness, fragmented sleep, and intrusions into wakefulness of elements of rapid eye movement (REM) sleep, including brief episodes of paralysis known as cataplexy. The orexin neuropeptides strongly excite many brain regions that regulate sleep/wake behavior, yet the key pathways through which orexins stabilize wakefulness and sleep remain unknown.Orexins act through two receptors, OX1R and OX2R (also known as HCRTR1 and HCRTR2), and the OX2R seems to play a critical role in the maintenance of wakefulness. Mice constitutively lacking OX2R are unable to maintain long bouts of wakefulness and can fall asleep rapidly (2). In addition, an OX2R antagonist strongly promotes sleep, whereas an OX1R antagonist has no effect (3).Although it is clear that OX2R signaling is necessary for the normal maintenance of wakefulness, the anatomic sites through which this occurs remain unknown. OX2R is expressed in many wake-promoting brain regions, including the histaminergic neurons of the tuberomammillary nucleus (TMN), other monoaminergic regions, cholinergic systems, and forebrain regions, including the thalamus and cortex (4). Several researchers have hypothesized that the TMN is a key site because orexin-A excites the TMN neurons and infusion of orexin-A near this region promotes wakefulness (5-7). However, this perspective is controversial as optogenetic activation of the orexin neurons promotes arousal in mice lacking histamine (8), and mice lacking both OX1...

show abstract

“…Nevertheless, selective OX1-R blockers have been found with SB 334867 (36) [185,186] and SB 674042 (37) and also OX2-R blockers have been characterized like JNJ-10394049 (38; 5 nM) and EMPA (39) (8 nM) [180,187] (Figure 8). Faedo et al [182] …”

Section: Non-peptide Ox-r Ligandsmentioning

confidence: 99%

Non-peptide ligands in the characterization of peptide receptors at the interface between neuroendocrine and mental diseases

Pissarek¹,

Disko²

2013

WJNS

View full text Add to dashboard Cite

Hypothalamic receptors for neuropeptide Y, melaninconcentrating hormone, melanocortins and orexins/ hypocretins as well as for the downstream signaling corticotrophic factor have been discussed broadly for their influence on food intake and reward but also on several psychiatric disorders. For the development of non-peptide ligands for the in vivo detection of alterations in density and affinity of such G-protein coupled (GPCRs) peptide receptors the requirements to affinity and pharmacokinetics have been shifted to thresholds markedly distict from classical GPCRs to dissociation constants < 0.5 nM, partition coefficients log P < 3.5 and transcellular transport ratios, e.g. for the permeability glycoprotein transporter, below 3. Nevertheless, a multitude of compounds has been reported originally as potential therapeutics in the treatment of obesity among which some are suitable candidates for labeling as PET or SPECT-tracers providing receptor affinities even below 0.1 nM. These could be unique tools not only for better understanding of the mechanism of obesity but also for investigations of extrahypothalamic role of "feeding receptors" at the interface between neuroendocrine and mental diseases.

show abstract

Biochemical and behavioural characterization of EMPA, a novel high‐affinity, selective antagonist for the OX₂ receptor

Cited by 88 publications

References 49 publications

Nonpeptide orexin type-2 receptor agonist ameliorates narcolepsy-cataplexy symptoms in mouse models

Nonpeptide orexin type-2 receptor agonist ameliorates narcolepsy-cataplexy symptoms in mouse models

Orexin receptor 2 expression in the posterior hypothalamus rescues sleepiness in narcoleptic mice

Non-peptide ligands in the characterization of peptide receptors at the interface between neuroendocrine and mental diseases

Contact Info

Product

Resources

About

Biochemical and behavioural characterization of EMPA, a novel high‐affinity, selective antagonist for the OX2 receptor

Cited by 88 publications

References 49 publications

Nonpeptide orexin type-2 receptor agonist ameliorates narcolepsy-cataplexy symptoms in mouse models

Nonpeptide orexin type-2 receptor agonist ameliorates narcolepsy-cataplexy symptoms in mouse models

Orexin receptor 2 expression in the posterior hypothalamus rescues sleepiness in narcoleptic mice

Non-peptide ligands in the characterization of peptide receptors at the interface between neuroendocrine and mental diseases

Contact Info

Product

Resources

About

Biochemical and behavioural characterization of EMPA, a novel high‐affinity, selective antagonist for the OX₂ receptor