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Stéphane OLIET





Phone : 33(0)5 57 57 37 37
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Cursus:
PhD, McGill University (1994)
Posdoc, UCSF (1994-1997) HFSP fellow
CR1 CNRS, Inserm U378(2001)
HDR, Université Bordeaux 2 (2003)
DR1 CNRS, Neurocentre Magendie Inserm (2009)

Expertise: Astrocyte, gliotransmitters, plasticity, synapse, NMDA receptors





95 publication(s) since Juillet 1991:


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* equal contribution
The indicated IF have been collected by the Web of Sciences in


28/03/2014 | Neuroscience   IF 3.2
Cannabinoid type-1 receptors in the paraventricular nucleus of the hypothalamus inhibit stimulated food intake.
Soria-Gomez E, Massa F, Bellocchio L, Rueda-Orozco PE, Ciofi P, Cota D, Oliet SH, Prospero-Garcia O, Marsicano G

Abstract:
Cannabinoid receptor type 1 (CB1)-dependent signaling in the brain is known to modulate food intake. Recent evidence has actually shown that CB1 can both inhibit and stimulate food intake in fasting/refeeding conditions, depending on the specific neuronal circuits involved. However, the exact brain sites where this bimodal control is exerted and the underlying neurobiological mechanisms are not fully understood yet. Using pharmacological and electrophysiological approaches, we show that local CB1 blockade in the paraventricular nucleus of the hypothalamus (PVN) increases fasting-induced hyperphagia in rats. Furthermore, local CB1 blockade in the PVN also increases the orexigenic effect of the gut hormone ghrelin in animals fed ad libitum. At the electrophysiological level, CB1 blockade in slices containing the PVN potentiates the decrease of the activity of PVN neurons induced by long-term application of ghrelin. Hence, the PVN is (one of) the site(s) where signals associated with the body's energy status determine the direction of the effects of endocannabinoid signaling on food intake.




19/02/2014 | Neuron   IF 14.4
Gliotransmitters travel in time and space.
Araque A, Carmignoto G, Haydon PG, Oliet SH, Robitaille R, Volterra A

Abstract:
The identification of the presence of active signaling between astrocytes and neurons in a process termed gliotransmission has caused a paradigm shift in our thinking about brain function. However, we are still in the early days of the conceptualization of how astrocytes influence synapses, neurons, networks, and ultimately behavior. In this Perspective, our goal is to identify emerging principles governing gliotransmission and consider the specific properties of this process that endow the astrocyte with unique functions in brain signal integration. We develop and present hypotheses aimed at reconciling confounding reports and define open questions to provide a conceptual framework for future studies. We propose that astrocytes mainly signal through high-affinity slowly desensitizing receptors to modulate neurons and perform integration in spatiotemporal domains complementary to those of neurons.




11/02/2014 | Nat Commun   IF 11.9
Neonatal testosterone suppresses a neuroendocrine pulse generator required for reproduction.
Israel JM, Cabelguen JM, Le Masson G, Oliet SH, Ciofi P

Abstract:
The pituitary gland releases hormones in a pulsatile fashion guaranteeing signalling efficiency. The determinants of pulsatility are poorly circumscribed. Here we show in magnocellular hypothalamo-neurohypophyseal oxytocin (OT) neurons that the bursting activity underlying the neurohormonal pulses necessary for parturition and the milk-ejection reflex is entirely driven by a female-specific central pattern generator (CPG). Surprisingly, this CPG is active in both male and female neonates, but is inactivated in males after the first week of life. CPG activity can be restored in males by orchidectomy or silenced in females by exogenous testosterone. This steroid effect is aromatase and caspase dependent, and is mediated via oestrogen receptor-alpha. This indicates the apoptosis of the CPG network during hypothalamic sexual differentiation, explaining why OT neurons do not burst in adult males. This supports the view that stereotypic neuroendocrine pulsatility is governed by CPGs, some of which are subjected to gender-specific perinatal programming.




2014 | J Physiol   IF 5
Extracellular signal-regulated kinase phosphorylation in forebrain neurones
contributes to osmoregulatory mechanisms

Dine J, Ducourneau V, Fenelon V, Fossat P, Amadio A, Eder M, Israel JM, Oliet SH, Voisin D

Abstract:





2014 | Pain   IF 6
Cancer pain is not necessarily correlated with spinal overexpression of reactive
glia markers

Ducourneau V*, Dolique T*, Hachem-Delaunay S, Miraucourt L, Amadio A, Blaszczyk L, Jacquot F, Ly J, Devoize L, Oliet SH, Dallel R, Mothet JP, Nagy F, Fenelon V*, Voisin D*

Abstract:
Bone cancer pain is a common and disruptive symptom in cancer patients. In cancer pain animal models, massive reactive astrogliosis in the dorsal horn of the spinal cord has been reported. Because astrocytes may behave as driving partners for pathological pain, we investigated the temporal development of pain behavior and reactive astrogliosis in a rat bone cancer pain model induced by injecting MRMT-1 rat mammary gland carcinoma cells into the tibia. Along with the development of bone lesions, a gradual mechanical and thermal allodynia and hyperalgesia as well as a reduced use of the affected limb developed in bone cancer-bearing animals, but not in sham-treated animals. Dorsal horn Fos expression after nonpainful palpation of the injected limb was also increased in bone cancer-bearing animals. However, at any time during the evolution of tumor, there was no increase in glial fibrillary acidic protein (GFAP) immunoreactivity in the dorsal horn. Further analysis at 21days after injection of the tumor showed no increase in GFAP and interleukin (IL) 1beta transcripts, number of superficial dorsal horn S100beta protein immunoreactive astrocytes, or immunoreactivity for microglial markers (OX-42 and Iba-1). In contrast, all these parameters were increased in the dorsal horn of rats 2weeks after sciatic nerve ligation. This suggests that in some cases, bone cancer pain may not be correlated with spinal overexpression of reactive glia markers, whereas neuropathic pain is. Glia may thus play different roles in the development and maintenance of chronic pain in these 2 situations.




2014 | Front Cell Neurosci   IF 3.9
Novel cell separation method for molecular analysis of neuron-astrocyte co-cultures.
Goudriaan A, Camargo N, Carney KE, Oliet SH, Smit AB, Verheijen MH

Abstract:
Over the last decade, the importance of astrocyte-neuron communication in neuronal development and synaptic plasticity has become increasingly clear. Since neuron-astrocyte interactions represent highly dynamic and reciprocal processes, we hypothesized that many astrocyte genes may be regulated as a consequence of their interactions with maturing neurons. In order to identify such neuron-responsive astrocyte genes in vitro, we sought to establish an expedited technique for separation of neurons from co-cultured astrocytes. Our newly established method makes use of cold jet, which exploits different adhesion characteristics of subpopulations of cells (Jirsova etal., 1997), and is rapid, performed under ice-cold conditions and avoids protease-mediated isolation of astrocytes or time-consuming centrifugation, yielding intact astrocyte mRNA with approximately 90% of neuronal RNA removed. Using this purification method, we executed genome-wide profiling in which RNA derived from astrocyte-only cultures was compared with astrocyte RNA derived from differentiating neuron-astrocyte co-cultures. Data analysis determined that many astrocytic mRNAs and biological processes are regulated by neuronal interaction. Our results validate the cold jet as an efficient method to separate astrocytes from neurons in co-culture, and reveals that neurons induce robust gene-expression changes in co-cultured astrocytes.




2014 | Front Aging Neurosci   IF 3.6
Astrocytosis in parkinsonism: considering tripartite striatal synapses in physiopathology?
Charron G, Doudnikoff E, Canron MH, Li Q, Vega C, Marais S, Baufreton J, Vital A, Oliet SH, Bezard E

Abstract:
The current concept of basal ganglia organization and function in physiological and pathophysiological conditions excludes the most numerous cells in the brain, i.e., the astrocytes, present with a ratio of 10:1 neuron. Their role in neurodegenerative condition such as Parkinson's disease (PD) remains to be elucidated. Before embarking into physiological investigations of the yet-to-be-identified 'tripartite' synapses in the basal ganglia in general and the striatum in particular, we therefore characterized anatomically the PD-related modifications in astrocytic morphology, the changes in astrocytic network connections and the consequences on the spatial relationship between astrocytic processes and asymmetric synapses in normal and PD-like conditions in experimental and human PD. Our results unravel a dramatic regulation of striatal astrocytosis supporting the hypothesis of a key role in (dys) regulating corticostriatal transmission. Astrocytes and their various properties might thus represent a therapeutic target in PD.




11/10/2013 | Pain   IF 6
Cancer pain is not necessarily correlated with spinal overexpression of reactive glia markers.
Ducourneau VR, Dolique T, Hachem-Delaunay S, Miraucourt LS, Amadio A, Blaszczyk L, Jacquot F, Ly J, Devoize L, Oliet SH, Dallel R, Mothet JP, Nagy F, Fenelon VS, Voisin DL

Abstract:
Bone cancer pain is a common and disruptive symptom in cancer patients. In cancer pain animal models, massive reactive astrogliosis in the dorsal horn of the spinal cord has been reported. Because astrocytes may behave as driving partners for pathological pain, we investigated the temporal development of pain behavior and reactive astrogliosis in a rat bone cancer pain model induced by injecting MRMT-1 rat mammary gland carcinoma cells into the tibia. Along with the development of bone lesions, a gradual mechanical and thermal allodynia and hyperalgesia as well as a reduced use of the affected limb developed in bone cancer-bearing animals, but not in sham-treated animals. Dorsal horn Fos expression after nonpainful palpation of the injected limb was also increased in bone cancer-bearing animals. However, at any time during the evolution of tumor, there was no increase in glial fibrillary acidic protein (GFAP) immunoreactivity in the dorsal horn. Further analysis at 21days after injection of the tumor showed no increase in GFAP and interleukin (IL) 1beta transcripts, number of superficial dorsal horn S100beta protein immunoreactive astrocytes, or immunoreactivity for microglial markers (OX-42 and Iba-1). In contrast, all these parameters were increased in the dorsal horn of rats 2weeks after sciatic nerve ligation. This suggests that in some cases, bone cancer pain may not be correlated with spinal overexpression of reactive glia markers, whereas neuropathic pain is. Glia may thus play different roles in the development and maintenance of chronic pain in these 2 situations.




03/2013 | Med Sci (Paris)   IF 0.4
[Importance of the location of NMDA glutamate receptors].
Oliet SH, Papouin T

Abstract:





2013 | J Med Chem   IF 6.1
Structural, Kinetic, and Pharmacodynamic Mechanisms of d-Amino Acid Oxidase Inhibition by Small Molecules
Hopkins SC, Heffernan MLR, Saraswat LD, Bowen CA, Melnick L, Hardy LW, Orsini MA, Allen MS, Koch P, Spear KL, Foglesong RJ , Soukri M, Chytil M, Fang QK, Jones SW, Varney MA, Panatier A, Oliet SHR, Pollegioni L, Piubelli L, Molla G, Nardini M, Large TH

Abstract:
We characterized the mechanism and pharmacodynamics of five structurally distinct inhibitors of d-amino acid oxidase. All inhibitors bound the oxidized form of human enzyme with affinity slightly higher than that of benzoate (Kd ≈ 2-4 μM). Stopped-flow experiments showed that pyrrole-based inhibitors possessed high affinity (Kd ≈ 100-200 nM) and slow release kinetics (k < 0.01 s(-1)) in the presence of substrate, while inhibitors with pendent aromatic groups altered conformations of the active site lid, as evidenced by X-ray crystallography, and showed slower kinetics of association. Rigid bioisosteres of benzoic acid induced a closed-lid conformation, had slower release in the presence of substrate, and were more potent than benzoate. Steady-state d-serine concentrations were described in a PK/PD model, and competition for d-serine sites on NMDA receptors was demonstrated in vivo. DAAO inhibition increased the spatiotemporal influence of glial-derived d-serine, suggesting localized effects on neuronal circuits where DAAO can exert a neuromodulatory role