References of "Charlier, Thierry"
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See detailDiversity of mechanisms involved in aromatase regulation and estrogen action in the brain
Charlier, Thierry ULg; Cornil, Charlotte ULg; Ball, Gregory et al

in Biochimica et Biophysica Acta - General Subjects (2010)

Background In recent years, the mechanisms through which estrogens modulate neuronal physiology, brain morphology, and behavior have proven to be far more complex than previously thought. For example, a ... [more ▼]

Background In recent years, the mechanisms through which estrogens modulate neuronal physiology, brain morphology, and behavior have proven to be far more complex than previously thought. For example, a second nuclear estrogen receptor has been identified, a new family of coregulatory proteins regulating steroid-dependent gene transcriptions was discovered and, finally, it has become clear that estrogens have surprisingly rapid effects based on their actions on cell membranes, which in turn result in the modulation of intracellular signaling cascades. Scope of review This paper presents a selective review of new findings in this area related to work in our laboratories, focusing on the role of estrogens in the activation of male sexual behavior. Two separate topics are considered. We first discuss functions of the steroid receptor coactivator-1 (SRC-1) that has emerged as a key limiting factor for behavioral effects of estradiol. Knocking-down its expression by antisense oligonucleotides drastically inhibits male-typical sexual behaviors. Secondly, we describe rapid regulations of brain estradiol production by calcium-dependent phosphorylations of the aromatase enzyme, themselves under the control of neurotransmitter activity. These rapid changes in estrogen bioavailability have clear behavioral consequences. Increases or decreases in estradiol concentrations respectively obtained by an acute injection of estradiol itself or of an aromatase inhibitor lead within 15–30 min to parallel changes in sexual behavior frequencies. These new controls of estrogen action offer a vast array of possibilities for discrete local controls of estrogen action. They also represent a formidable challenge for neuroendocrinologists trying to obtain an integrated view of brain function in relation to behavior. [less ▲]

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See detailOwn song selectivity in the songbird auditory pathway: suppression by norepinephrine
Poirier, Colline; Boumans, Tiny; Vellema, Michiel et al

Poster (2010)

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See detailBrain aromatase activity and male sexual behavior
Balthazart, Jacques ULg; Cornil, Charlotte ULg; Charlier, Thierry ULg et al

in Annales d'Endocrinologie (2010), 71

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See detailSex steroid-induced neuroplasticity and behavioral activation in birds
Balthazart, Jacques ULg; Charlier, Thierry ULg; Barker, Jennifer ULg et al

in European Journal of Neuroscience (2010), 32

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See detail17β-estradiol levels in male zebra finch brain: combining Palkovits punch and an ultrasensitive radioimmunoassay
Charlier, Thierry ULg; Po, Kevin WL; Newman, Amy EM et al

in General and Comparative Endocrinology (2010), 167

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See detailRapid regulation of aromatase activity and the role of stress
Dickens, Molly; Charlier, Thierry ULg; Cornil, Charlotte ULg et al

Poster (2010)

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See detailEstradiol, a key endocrine signal in the sexual differentiation and activation of reproductive behavior in quail.
Balthazart, Jacques ULg; Cornil, Charlotte ULg; Charlier, Thierry ULg et al

in Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology (2009), 311(5), 323-45

In Japanese quail, estrogen's effects on sexual behavior can be divided into three classes based on the underlying mechanisms and time-course of action and release. During embryonic life, the embryonic ... [more ▼]

In Japanese quail, estrogen's effects on sexual behavior can be divided into three classes based on the underlying mechanisms and time-course of action and release. During embryonic life, the embryonic ovary secretes large amounts of estrogens. In contrast to what is observed in mammals where sexual differentiation essentially proceeds via masculinization of the males, in quail, females are demasculinized by their endogenous ovarian estrogens, an effect that can be blocked by injection of an aromatase inhibitor and mimicked in male embryos by an injection of estradiol. In adulthood, testosterone secreted by the testes is converted into estrogens by the preoptic aromatase. Locally produced estrogens activate male sexual behavior largely through the activation of estrogen receptors resulting in the transcription of a variety of genes, including brain aromatase (genomic effect). Both changes in estrogen production and action are observed within latencies ranging from a few hours to a few days, and are completely reversible. Additionally, brain aromatase activity can be modulated within minutes by calcium-dependent phosphorylations, triggered by variations in glutamatergic neurotransmission. These rapid changes in aromatase activity affect with relatively short latencies (10-15 min) the expression of male sexual behavior in quail and also in mice. Overall, the effects of estrogens on sexual behavior can thus be categorized into three classes: organizational (irreversible genomic action during ontogeny), activational (reversible genomic action during adulthood) and rapid nongenomic effects. Rapid and slower changes in brain aromatase activity match well with the two modes of estrogen action on behavior and provide temporal variations in the estrogens' bioavailability that should be able to support the entire range of established effects for this steroid. [less ▲]

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See detailWho's in charge? Nuclear receptor coactivator function in brain and behavior
Charlier, Thierry ULg

Scientific conference (2009)

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See detailThe fast regulation of aromatase activity by phosphorylations is species and tissue-independent.
Charlier, Thierry ULg; Harada, Nobuhiro; Ball, Gregory F. et al

Poster (2009)

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See detailSpecies and tissue-independent rapid regulation of aromatase activity by phosphorylations.
Charlier, Thierry ULg; Harada, Nobuhiro; Ball, Gregory F. et al

in Acta Neurologica Belgica (2009)

Aromatase activity (AA) is rapidly inhibited in male quail brains, following expression of sexual behavior, activation of glutamatergic receptors or exposure to phosphorylating conditions. Questions ... [more ▼]

Aromatase activity (AA) is rapidly inhibited in male quail brains, following expression of sexual behavior, activation of glutamatergic receptors or exposure to phosphorylating conditions. Questions remain as to whether direct aromatase phosphorylation is the common key regulatory mechanism and whether these inhibitions are specific to quail hypothalamus. We now showed that AA is rapidly downregulated in quail ovary homogenates incubated in phosphorylating conditions, similarly to what is observed in hypothalamic homogenates. To understand the processes underlying this control, we expressed human aromatase in the human cell line HEK293 and 1) researched whether human aromatase can also be rapidly modulated by phosphorylations and 2) investigated more precisely the processes involved in this rapid control of activity. AA in HEK293 was rapidly inhibited following depolarization of intact cells with 100 mM KCl or in cell lysates exposed to phosphorylating conditions. Thus inhibition of AA in phosphorylating conditions is not unique to the quail hypothalamus neural environment but seems to be a general process. We are now defining the contribution of single residues of the aromatase protein to this enzymatic control. [less ▲]

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