Radiprodil, a selective GluN2B negative allosteric modulator, rescues audiogenic seizures in mice carrying the GluN2A(N615S) mutation.

Background And Purpose: GRIN-related disorders are neurodevelopmental disorders caused by mutations in N-methyl-D-aspartate receptor (NMDAR) subunit genes. A large fraction of these mutations lead to a 'gain of function' (GoF) of the NMDAR. Patients present with a range of symptoms including epilepsy, intellectual disability, behavioural and motor.

Pre- and postsynaptic N-methyl-D-aspartate receptors are required for sequential printing of fear memory engrams.

The organization of fear memory involves the participation of multiple brain regions. However, it is largely unknown how fear memory is formed, which circuit pathways are used for "printing" memory engrams across brain regions, and the role of identified brain circuits in memory retrieval. With advanced genetic methods, we combinatorially blocked presynaptic output and manipulated N-methyl-D-aspartate receptor (NMDAR) in the basolateral amygdala (BLA) and medial prefrontal cortex (mPFC) before and after cued fear conditioning.

Hypothalamic NPY-Y1R Interacts with Gonadal Hormones in Protecting Female Mice against Obesity and Neuroinflammation.

We previously demonstrated that Npy1r mice, which carry the conditional inactivation of the gene in forebrain principal neurons, display a sexually dimorphic phenotype, with male mice showing metabolic, hormonal and behavioral effects and females being only marginally affected. Moreover, exposure of Npy1r male mice to a high-fat diet (HFD) increased body weight growth, adipose tissue, blood glucose levels and caloric intake compared to Npy1r male controls. We used conditional knockout Npy1r and Npy1r control mice to examine whether forebrain disruption of the gene affects susceptibility to obesity and associated disorders of cycling and ovariectomized (ovx) female mice in a standard diet (SD) regimen or exposed to an HFD for 3 months.

Chemical Oral Cancerogenesis Is Impaired in PI3Kγ Knockout and Kinase-Dead Mice.

We investigated the role of PI3Kγ in oral carcinogenesis by using a murine model of oral squamous carcinoma generated by exposure to 4-nitroquinoline 1-oxide (4NQO) and the continuous human cancer cell line HSC-2 and Cal-27. PI3Kγ knockout (not expressing PI3Kγ), PI3Kγ kinase-dead (carrying a mutation in the PI3Kγ gene causing loss of kinase activity) and wild-type (WT) C57Bl/6 mice were administered 4NQO via drinking water to induce oral carcinomas. At sacrifice, lesions were histologically examined and stained for prognostic tumoral markers (EGFR, Neu, cKit, Ki67) and inflammatory infiltrate (CD3, CD4, CD8, CD19 and CD68).

NPY-Y1 receptor signaling controls spatial learning and perineuronal net expression.

Perineuronal nets (PNNs) are extracellular matrix structures that form around some types of neurons at the end of critical periods, limiting neuronal plasticity. In the adult brain, PNNs play a crucial role in the regulation of learning and cognitive processes. Neuropeptide Y (NPY) is involved in the regulation of many physiological functions, including learning and memory abilities, via activation of Y1 receptors (Y1Rs).

Sex differences in behavioral and metabolic effects of gene inactivation: The neuropeptide Y and Y receptors in the brain.

Brain and gonadal hormones interplay controls metabolic and behavioral functions in a sex-related manner. However, most translational neuroscience research related to animal models of endocrine and psychiatric disorders are often carried out in male animals only. The Neuropeptide Y (NPY) system shows sex-dependent differences and is sensitive to gonadal steroids.

Conditional inactivation of Npy1r gene in mice induces sex-related differences of metabolic and behavioral functions.

Sex hormone-driven differences in gene expression have been identified in experimental animals, highlighting brain neuronal populations implicated in dimorphism of metabolic and behavioral functions. Neuropeptide Y-Y1 receptor (NPY-Y1R) system is sexually dimorphic and sensitive to gonadal steroids. In the present study we compared the phenotype of male and female conditional knockout mice (Npy1r mice), carrying the inactivation of Npy1r gene in excitatory neurons of the brain limbic system.

Conditional inactivation of Npy1r gene in mice induces behavioural inflexibility and orbitofrontal cortex hyperactivity that are reversed by escitalopram.

Cognitive flexibility is the ability to rapidly adapt established patterns of behaviour in the face of changing circumstance and depends critically on the orbitofrontal cortex (OFC). Impaired flexibility also results from altered serotonin transmission in the OFC. The Y1 (Y1R) and Y5 (Y5R) receptors for neuropeptide Y (NPY) colocalize in several brain regions and have overlapping functions in regulating cognition and emotional behaviour.

Liver ERα regulates AgRP neuronal activity in the arcuate nucleus of female mice.

Recent work revealed the major role played by liver Estrogen Receptor α (ERα) in the regulation of metabolic and reproductive functions. By using mutant mice with liver-specific ablation of Erα, we here demonstrate that the hepatic ERα is essential for the modulation of the activity of Agouti Related Protein (AgRP) neurons in relation to the reproductive cycle and diet. Our results suggest that the alterations of hepatic lipid metabolism due to the lack of liver ERα activity are responsible for a neuroinflammatory status that induces refractoriness of AgRP neurons to reproductive and dietary stimuli.

Reduced NPY Y1 receptor hippocampal expression and signs of decreased vagal modulation of heart rate in mice.

Central neuropeptide Y (NPY) signaling participates in the regulation of cardiac autonomic outflow, particularly via activation of NPY-Y1 receptors (Y1Rs). However, the specific brain areas and neural pathways involved have not been completely identified yet. Here, we evaluate the role of hippocampal Y1Rs in the modulation of the autonomic control of cardiac function using a conditional knockout mouse model.

Sex-dependent regulation of hypothalamic neuropeptide Y-Y1 receptor gene expression in leptin treated obese (ob/ob) or lean mice.

Pharmacological and genetic studies have shown that the Y receptor (YR) for Neuropeptide Y (NPY) plays a crucial role in the control of feeding behavior under metabolic conditions of low leptin levels or leptin deficiency. In this study, we investigated the effect of leptin deficiency and leptin replacement on YR gene expression in the hypothalamus of lean and obese YR/LacZ transgenic mice (TgYR/LacZ) carrying the murine Y1R promoter linked to the LacZ gene that induces the expression of β-galactosidase. Two daily intraperitoneal injections with leptin (1μg/g of body weight for one week) of male and female lean (TgYR/LacZ) and obese (TgYR/LacZ) mice induced a significant decrease of body weight in both sexes and genotypes.

NPY-Y1 coexpressed with NPY-Y5 receptors modulate anxiety but not mild social stress response in mice.

The Y1 and Y5 receptors for neuropeptide Y have overlapping functions in regulating anxiety. We previously demonstrated that conditional removal of the Y1 receptor in the Y5 receptor expressing neurons in juvenile Npy1r(Y5R-/-) mice leads to higher anxiety but no changes in hypothalamus-pituitary-adrenocortical axis activity, under basal conditions or after acute restraint stress. In the present study, we used the same conditional system to analyze the specific contribution of limbic neurons coexpressing Y1 and Y5 receptors on the emotional and neuroendocrine responses to social chronic stress, using different housing conditions (isolation vs.

Conditional inactivation of neuropeptide Y Y1 receptors unravels the role of Y1 and Y5 receptors coexpressing neurons in anxiety.

Background: The Y1 receptor (Y1R) and Y5 receptor (Y5R) for neuropeptide Y share similar actions in the regulation of anxiety. Previously demonstrated that conditional removal of the Y1R during postnatal development in the forebrain excitatory neurons leads to higher anxiety, increased hypothalamus-pituitary-adrenocortical axis activity, and decreased body growth rate in male mice raised by foster mothers that exhibit high levels of maternal care. In the present study, we used the same conditional system to analyze the specific contribution to emotional behavior and stress response of the Y1R coexpressed with the Y5R.

Regulatory functions of limbic Y1 receptors in body weight and anxiety uncovered by conditional knockout and maternal care.

Neuropeptide Y (NPY) plays an important role in stress, anxiety, obesity, and energy homeostasis via activation of NPY-Y1 receptors (Y1Rs) in the brain. However, global knockout of the Npy1r gene has low or no impact on anxiety and body weight. To uncover the role of limbic Y1Rs, we generated conditional knockout mice in which the inactivation of the Npy1r gene was restricted to excitatory neurons of the forebrain, starting from juvenile stages (Npy1r(rfb)).

Treatment of newborn G6pc(-/-) mice with bone marrow-derived myelomonocytes induces liver repair.

Background & Aims: Several studies have shown that bone marrow-derived committed myelomonocytic cells can repopulate diseased livers by fusing with host hepatocytes and can restore normal liver function. These data suggest that myelomonocyte transplantation could be a promising approach for targeted and well-tolerated cell therapy aimed at liver regeneration. We sought to determine whether bone marrow-derived myelomonocytic cells could be effective for liver reconstitution in newborn mice knock-out for glucose-6-phosphatase-α.

Expression patterns of promoters for NPY Y(1) and Y(5) receptors in Y(5)RitTA and Y(1)RVenus BAC-transgenic mice.

In the rat brain, neuropeptide Y (NPY) Y(1) and Y(5) receptors are coexpressed in various forebrain regions where they mediate several NPY-activated functions, including feeding behaviour, anxiety, neuronal excitability and hormone secretion. We studied the distribution pattern and cellular colocalization of the Y(1) and the Y(5) receptor gene expression in the mouse brain by using transgenic mice with genomically integrated BAC clones, where the coding regions of the Y(1) and Y(5) receptor genes were replaced by Venus and the synthetic transcription factor itTA reporter genes, respectively (Tg(Y5RitTA/Y1RVenus) mice). Analysis of Venus fluorescence and itTA-mediated activation of Cre recombinase revealed copy number-dependent expression levels, between the lines, but similar expression patterns.

Physiology and gene regulation of the brain NPY Y1 receptor.

Neuropeptide Y (NPY) is one of the most prominent and abundant neuropeptides in the mammalian brain where it interacts with a family of G-protein coupled receptors, including the Y(1) receptor subtype (Y(1)R). NPY-Y(1)R signalling plays a prominent role in the regulation of several behavioural and physiological functions including feeding behaviour and energy balance, sexual hormone secretion, stress response, emotional behaviour, neuronal excitability and ethanol drinking. Y(1)R expression is regulated by neuronal activity and peripheral hormones.

Role of brain neuroactive steroids in the functional interplay between the GABA(A) and the NPY-Y1 receptor mediated signals in the amygdala.

Various lines of evidence suggest a functional interaction between GABA(A) and Neuropeptide Y (NPY)-Y(1) receptor (Y(1)R) mediated transmissions in various brain regions, which can be important in the regulation of sedation, feeding, anxious behaviour and neuronal excitability. By using a transgenic mouse model carrying the murine Y(1)R gene promoter fused to the lacZ reporter gene (Y(1)R/LacZ mice), we showed that prolonged pharmacologically or physiologically induced changes in the cerebrocortical concentrations of the neuroactive steroids 3alpha-hydroxy-5alpha-pregnan- 20-one (3alpha,5alpha TH PROG) and tetrahydrodeoxycorticosterone (3alpha,5alpha TH DOC) increases Y(1)R/LacZ transgene expression in the central and medial amygdala, an effect similar to that induced by long-term treatment with positive modulators of the GABA(A) receptor complex (diazepam or abecarnil). We also demonstrated that fluctuations in the cerebrocortical concentrations of 3alpha,5alpha-TH PROG and 3alpha,5alpha TH DOC during voluntary ethanol consumption and ethanol withdrawal induces a marked increase in Y(1)R gene expression that becomes apparent 48 h after withdrawal.

Loss of zolpidem efficacy in the hippocampus of mice with the GABAA receptor gamma2 F77I point mutation.

Zolpidem is a hypnotic benzodiazepine site agonist with some gamma-aminobutyric acid (GABA)(A) receptor subtype selectivity. Here, we have tested the effects of zolpidem on the hippocampus of gamma2 subunit (gamma2F77I) point mutant mice. Analysis of forebrain GABA(A) receptor expression with immunocytochemistry, quantitative [(3)H]muscimol and [(35)S] t-butylbicyclophosphorothionate (TBPS) autoradiography, membrane binding with [(3)H]flunitrazepam and [(3)H]muscimol, and comparison of miniature inhibitory postsynaptic current (mIPSC) parameters did not reveal any differences between homozygous gamma2I77/I77 and gamma2F77/F77 mice.

Agonistic effects of the beta-carboline DMCM revealed in GABA(A) receptor gamma 2 subunit F77I point-mutated mice.

Affinity of the inverse agonist methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) to the benzodiazepine binding site of the GABA(A) receptor is abolished by a phenylalanine (F) to isoleucine (I) substitution at position 77 of the gamma2 subunit. We tested the effects of DMCM in gene knockin gamma2I77 mice carrying this mutation. Unlike in wild-type mice, DMCM was not able to reverse the GABA-induced reduction of the picrotoxin-sensitive t-butylbicyclophosphoro-[35S]thionate ([35S]TBPS) binding to GABA(A) receptor channels in the forebrain sections of gamma2I77 mice.

Neuroanatomical and pharmacological evidence for a functional interaction between GABAergic and NPY-Y1 transmission in the amygdala of Y1R/LacZ transgenic mice.

Several lines of evidence indicate that GABA and neuropeptide Y (NPY) are functionally coupled and may interact in the regulation of fear- and anxiety-induced behavior. Neuroanatomical studies demonstrated that GABA and NPY coexist in neurons of the amygdaloid complex and that NPY may directly modulate the activity of GABAergic neurons by stimulating Y1 receptors. By using a transgenic mouse model harboring a construct comprising the murine Y1 receptor gene promoter fused to a lacZ reporter gene (Y1R/LacZ mice), we showed that long-term treatment with positive (diazepam or abecarnil) or negative (FG7142) modulators of GABAA receptor function induced a marked increase or decrease, respectively, in Y1 receptor gene expression in the amygdala.

Affinity of various benzodiazepine site ligands in mice with a point mutation in the GABA(A) receptor gamma2 subunit.

The benzodiazepine binding site of GABA(A) receptors is located at the interface of the alpha and gamma subunits. Certain point mutations in these subunits have been demonstrated to dramatically reduce the affinity of benzodiazepine binding site ligands for these receptors. Recently, mice were generated with a phenylalanine (F) to isoleucine (I) substitution at position 77 in the gamma2 subunit of GABA(A) receptors.

Increased expression of the gene for the Y1 receptor of neuropeptide Y in the amygdala and paraventricular nucleus of Y1R/LacZ transgenic mice in response to restraint stress.

A sustained increase in the brain concentrations of neuroactive steroids was previously shown to induce Y1 receptor gene expression in the amygdala of Y1R/LacZ transgenic mice which harbour a construct comprising the murine Y1 receptor gene promoter and the lacZ reporter gene. We now investigated the effects of restraint stress on both the cerebrocortical concentrations of neuroactive steroids and Y1 receptor gene expression in the amygdala and hypothalamic paraventricular nucleus (PVN) of Y1R/LacZ transgenic mice. The cerebrocortical concentrations of allopregnanolone and allotetrahydrodeoxycorticosterone were significantly increased immediately after a 1-h exposure to restraint stress and had returned to control values within 30 min.

Abolition of zolpidem sensitivity in mice with a point mutation in the GABAA receptor gamma2 subunit.

Agonists of the allosteric benzodiazepine site of GABAA receptors bind at the interface of the alpha and gamma subunits. Here, we tested the in vivo contribution of the gamma2 subunit to the actions of zolpidem, an alpha1 subunit selective benzodiazepine agonist, by generating mice with a phenylalanine (F) to isoleucine (I) substitution at position 77 in the gamma2 subunit. The gamma2F77I mutation has no major effect on the expression of GABAA receptor subunits in the cerebellum.