Anxiety- and depression-related disorders are frequently associated with deficits in social behavior, including excessive aggression and violence, which may arise from disruptions in the neural circuits regulating emotions and social interactions. Sex differences play a crucial role in modulating emotional and social behaviors, particularly aggression and anxiety. Neuropeptide Y (NPY) and its Y1 receptor (Y1R) are involved in regulating various physiological functions, including emotional behavior and stress response. We previously demonstrated that conditional knockout of Npy1r gene in the forebrain excitatory neurons (Npy1rrfb mutant mice) increased anxiety-like behavior and hypothalamus-pituitary-adrenocortical axis reactivity and decreased body weight growth in a sex-dependent manner. In the present study we investigated how the depletion of the Npy1r gene in limbic areas might affect male and female mice by using a test battery aimed at assessing anxiety-like, social and aggressive behavior as well as response to novelty. Our results showed reduced exploratory behavior and increased anxiety in response to a novel environment in Npy1rrfb mice, with females exhibiting more pronounced effects. In contrast, only Npy1rrfb males showed reduced neophobia and increased impulsivity in response to a novel palatable food. Moreover, reduced limbic Npy1r expression decreased territorial aggression and increased defensive behaviors only in males. These findings reveal that limbic Y1R modulates anxiety, social interaction, and aggression in a sex-dependent manner. Moreover, they uncover a novel role for Y1R in regulating intermale aggression and suggest sex-specific links between NPY-Y1R signaling and the modulation of motivational and emotional responses.

Postsynaptic density (PSD) is a tightly interconnected protein network ensuring synaptic function through the interaction of neurotransmitter receptors, structural adaptor proteins, and signaling molecules. Disruption of PSD may cause neurological diseases, including autism spectrum disorders and cognitive impairment. We demonstrate that the SKT adaptor distinctly localizes within dendritic spines as an integral component of the synaptic network, binding PSD-95 and SHANK3. SKT-knockout (KO) mice show significant abnormalities in dendritic spine density and morphology, consistent with RhoA and Rac1 GTPase dysregulated activity. KO-derived neuronal cultures display delayed neuronal synchronization and maturation associated with glutamatergic pre- and postsynaptic impairment. Behavioral tests on KO mice reveal increased self-grooming activity and impaired motor coordination, with altered cognitive and executive functions compared to wild-type mice. Overall, SKT emerges as a key contributor to the structural and functional PSD organization, regulating synaptic function through its interactions with PSD components.

Background and PurposeGRIN‐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. Controlling seizures is a significant unmet medical need in most patients with GRIN‐related disorders. Although several hundred GRIN mutations have been identified in humans, until recently none of the mouse models carrying Grin mutations/deletions showed an epileptic phenotype. The two recent exceptions both carry mutations of GluN2A. The aim of this study was to assess the efficacy of radiprodil, a selective negative allosteric modulator of GluN2B‐containing NMDARs, in counteracting audiogenic seizures (AGS) in a murine model carrying the GluN2A(N615S) homozygous mutation (Grin2aS/S mice).Experimental ApproachGrin2aS/S mice were acutely treated with radiprodil at different doses before the presentation of a high‐frequency acoustic stimulus commonly used for AGS induction.Key ResultsRadiprodil significantly and dose‐dependently reduced the onset and severity of AGS in Grin2aS/S mice. Surprisingly, the results revealed a sex‐dependent difference in AGS susceptibility and in the dose‐dependent protection of radiprodil in the two genders. Specifically, radiprodil was more effective in female versus male mice.Conclusion and ImplicationsOverall, our data clearly show that radiprodil, a GluN2B selective negative allosteric modulator, may have the potential to control seizures in patients with GRIN2A GoF mutations. Further studies are warranted to better understand the sex‐dependent effects observed in this study.

Diets rich in fat and sugars evoke chronic low-grade inflammation, leading to metabolic derangements. This study investigates the impact of fructose and galactose, two commonly consumed simple sugars, on exacerbation of the harmful effects caused by high fat intake. Additionally, the potential efficacy of fructooligosaccharides (FOS), a fermentable dietary fiber, in counteracting these effects is examined.Male Sprague-Dawley rats (six/group) are fed 8 weeks as follows: control 5% fat diet (CNT), 20% fat diet (FAT), FAT+10% FOS diet (FAT+FOS), FAT+25% galactose diet (FAT+GAL), FAT+GAL+10% FOS diet (FAT+GAL+FOS), FAT+25% fructose diet (FAT+FRU), FAT+FRU+10% FOS diet (FAT+FRU+FOS). The dietary manipulations tested do not affect body weight gain, blood glucose, or markers of systemic inflammation whereas significant increases in plasma concentrations of triacylglycerols, cholesterol, aspartate aminotransferase, and alanine aminotrasferase are detected in both FAT+FRU and FAT+GAL compared to CNT. In the liver and skeletal muscle, both sugars induce significant accumulation of lipids and advanced glycation end-products (AGEs). FOS supplementation prevents these impairments.This study extends the understanding of the deleterious effects of a chronic intake of simple sugars and demonstrates the beneficial role of the prebiotic FOS in dampening the sugar-induced metabolic impairments by prevention of lipid and AGEs accumulation.

We tested the pro-angiogenic and anti-inflammatory effects of human placenta-derived mesenchymal stromal cells (hPDMSCs)-derived conditioned media (CM) on a mouse model of preeclampsia (PE), a severe human pregnancy-related syndrome characterized by maternal hypertension, proteinuria, endothelial damage, inflammation, often associated with fetal growth restriction (FGR). At d11 of pregnancy, PE was induced in pregnant C57BL/6N mice by bacterial lipopolysaccharide (LPS) intravenous injection. At d12, 300 μL of unconditioned media (control group) or 300 μL PDMSCs-CM (CM group) were injected. Maternal systolic blood pressure was measured from 9 to 18 days of pregnancy. Urine protein content were analyzed at days 12, 13, and 17 of pregnancy. At d19, mice were sacrificed. Number of fetuses, FGR, fetal reabsorption, and placental weight were evaluated. Placentae were analyzed for sFlt-1, IL-6, and TNF-α gene and protein expressions. No FGR and/or reabsorbed fetuses were delivered by PDMSCs-CM-treated PE mice, while five FGR fetuses were found in the control group accompanied by a lower placental weight. PDMSCs-CM injection significantly decreased maternal systolic blood pressure, proteinuria, sFlt-1, IL-6, and TNF-α levels in PE mice. Our data indicate that hPDMSCs-CM can reverse PE-like features during pregnancy, suggesting a therapeutic role for hPDMSCs for the treatment of preeclampsia.

We previously demonstrated that Npy1rrfb mice, which carry the conditional inactivation of the Npy1r 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 Npy1rrfb male mice to a high-fat diet (HFD) increased body weight growth, adipose tissue, blood glucose levels and caloric intake compared to Npy1r2lox male controls. We used conditional knockout Npy1rrfb and Npy1r2lox control mice to examine whether forebrain disruption of the Npy1r 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. The conditional deletion of the Npy1r gene increased body weight and subcutaneous white adipose tissue weight in both SD- and HFD-fed ovx females but not in cycling females. Moreover, compared with ovx control females on the same diet regimen, Npy1rrfb females displayed increased microglia number and activation, increased expression of Neuropeptide Y (NPY)-immunoreactivity (IR) and decreased expression of proopiomelanocortin-IR in the hypothalamic arcuate nucleus (ARC). These results suggest that in the ARC NPY-Y1R reduces the susceptibility to obesity of female mice with low levels of gonadal hormones and that this effect may be mediated via NPY-Y1R ability to protect the brain against neuroinflammation.

NPY and its Y1 cognate receptor (Y1R) have been shown to be involved in the regulation of stress, anxiety, depression and energy homeostasis. We previously demonstrated that conditional knockout of Npy1r gene in the excitatory neurons of the forebrain of adolescent male mice (Npy1rrfb mice) decreased body weight growth and adipose tissue and increased anxiety. In the present study, we used the same conditional system to examine whether the targeted disruption of the Npy1r gene in limbic areas might affect susceptibility to obesity and associated disorders during adulthood in response to a 3-week high-fat diet (HFD) regimen. We demonstrated that following HFD exposure, Npy1rrfb male mice showed increased body weight, visceral adipose tissue, and blood glucose levels, hyperphagia and a dysregulation of calory intake as compared to control Npy1r2lox mice. These results suggest that low expression of Npy1r in limbic areas impairs habituation to high caloric food and causes high susceptibility to diet-induced obesity and glucose intolerance in male mice, uncovering a specific contribution of the limbic Npy1r gene in the dysregulation of the eating/satiety balance.

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(rfb) mice), carrying the inactivation of Npy1r gene in excitatory neurons of the brain limbic system. Compared to their male control (Npy1r(2lox)) littermates, male Npy1r(rfb) mice exhibited hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis that is associated with anxiety and executive dysfunction, reduced body weight growth, after-fasting refeeding, white adipose tissue (WAT) mass and plasma leptin levels. Conversely, female Npy1r(rfb) mice displayed an anxious-like behavior but no differences in HPA axis activity, executive function and body weight, compared to control females. Moreover, conditional inactivation of Npy1r gene induced an increase of subcutaneous and gonadal WAT weight and plasma leptin levels and a compensatory decrease of Agouti-related protein immunoreactivity in the hypothalamic arcuate (ARC) nucleus in females, compared to their respective control littermates. Interestingly, Npy1r mRNA expression was reduced in the ARC and in the paraventricular hypothalamic nuclei of female, but not male mice. These results demonstrated that female mice are resilient to hormonal and metabolic effects of limbic Npy1r gene inactivation, suggesting the existence of an estrogen-dependent relay necessary to ensure the maintenance of the homeostasis, that can be mediated by hypothalamic Y1R.

Target-derived growth factors that regulate neuronal survival and differentiation, and maintain neuronal phenotype may be of critical importance for normal development and mature function of the central nervous system (CNS). This chapter describes the main physiological features of nerve growth factor (NGF) in the CNS. It explains the molecular structure of the NGF receptors and their functional properties and interaction. The chapter summarizes the current knowledge on the effect of NGF on basal forebrain and striatal cholinergic neurons. Degenerative changes in the basal forebrain cholinergic system have been suggested to play a critical role in the development of dementia in Alzheimer's disease. The finding that NGF plays a role in trophic support of basal forebrain cholinergic neurons has provoked speculation that a decline in NGF-related mechanisms may be involved in the pathogenesis of Alzheimer's disease and that agents mimicking its function may be beneficial for the clinical treatment of this disease.

COVID-19, the illness caused by SARS-CoV-2, has a wide-ranging clinical spectrum that, in the worst-case scenario, involves a rapid progression to severe acute respiratory syndrome and death. Epidemiological data show that obesity and diabetes are among the main risk factors associated with high morbidity and mortality. The increased susceptibility to SARS-CoV-2 infection documented in obesity-related metabolic derangements argues for initial defects in defence mechanisms, most likely due to an elevated systemic metabolic inflammation ("metaflammation"). The NLRP3 inflammasome is a master regulator of metaflammation and has a pivotal role in the pathophysiology of either obesity or diabetes. Here, we discuss the most recent findings suggesting contribution of NLRP3 inflammasome to the increase in complications in COVID-19 patients with diabesity. We also review current pharmacological strategies for COVID-19, focusing on treatments whose efficacy could be due, at least in part, to interference with the activation of the NLRP3 inflammasome. LINKED ARTICLES: This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.

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). Here we demonstrated that the conditional depletion of the gene encoding the Y1R for NPY in adult forebrain excitatory neurons (Npy1r(rfb) mutant mice), induces a significant slowdown in spatial learning, which is associated with a robust intensification of PNN expression and an increase in the number of c-Fos expressing cells in the cornus ammonis 1 (CA1) of the dorsal hippocampus. Importantly, the enzymatic digestion of PNNs in CA1 normalizes c-Fos activity and completely rescues learning abilities of Npy1r(rfb) mice. These data highlight a previously unknown functional link between NPY-Y1R transmission and PNNs, which may play a role in the control of dorsal hippocampal excitability and related cognitive functions.

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. Based on published data from our and other laboratories, in this review we will discuss the sex related differences of NPY action on energy balance, bone homeostasis and behavior in rodents with the genetic manipulation of genes encoding NPY and its Y1, Y2 and Y5 cognate receptors. Comparative analyses of the phenotype of transgenic and knockout NPY and Y receptor rodents unravels sex dependent differences in the functions of this neurotransmission system, potentially helping to develop therapeutics for a variety of sex-related disorders including metabolic syndrome, osteoporosis and ethanol addiction.

Acute itch can be generated by either chemical or mechanical stimuli, which activate separate pathways in the periphery and spinal cord. While substantial progress has been made in mapping the transmission pathway for chemical itch, the central pathway for mechanical itch remains obscure. Using complementary genetic and pharmacological manipulations, we show that excitatory neurons marked by the expression of the neuropeptide Y1 receptor (Y1(Cre) neurons) form an essential pathway in the dorsal spinal cord for the transmission of mechanical but not chemical itch. Ablating or silencing the Y1(Cre) neurons abrogates mechanical itch, while chemogenetic activation induces scratching. Moreover, using Y1 conditional knockout mice, we demonstrate that endogenous neuropeptide Y (NPY) acts via dorsal-horn Y1-expressing neurons to suppress light punctate touch and mechanical itch stimuli. NPY-Y1 signaling thus regulates the transmission of innocuous tactile information by establishing biologically relevant thresholds for touch discrimination and mechanical itch reflexes.

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. The targeted disruption of gene encoding Y1R (Npy1r gene) in Y5R containing neurons (Npy1rY5R−/− mice) increases anxiety-like behaviour and spatial reference memory. Here we used the same conditional system to analyse whether the coordinated expression of the Y1R and Y5R might be required for behavioural flexibility in reversal learning tasks, OFC serotoninergic tone and OFC neural activity, as detected by immunohistochemical quantification of the immediate-early gene, c-Fos. In addition, we investigated whether the acute treatment of Npy1rY5R−/− mice with the selective serotonin reuptake inhibitor escitalopram affected behavioural flexibility and OFC c-Fos expression. Npy1rY5R−/− male mice exhibit an impairment in performing the reversal task of the Morris water maze and the water T-maze but normal spatial learning, working memory and sociability, compared to their control siblings. Furthermore, Npy1rY5R−/− male mice display decreased 5-hydroxytriptamine (5-HT) positive fibres and increased baseline neural activity in OFC. Importantly, escitalopram normalizes OFC neural activity and restores behavioural flexibility of Npy1rY5R−/− male mice. These findings suggest that the inactivation of Y1R in Y5R containing neurons increases pyramidal neuron activity and dysregulates serotoninergic tone in OFC, whereby contributing to reversal learning impairment.

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. Radiotelemetric transmitters were implanted in 4-month-old male mice exhibiting reduced forebrain expression (rfb) of the Y1R (Npy1rrfb, n=10) and their corresponding controls (Npy1r2lox, n=8). ECG signals were recorded (i) during resting conditions, (ii) under selective pharmacological manipulation of cardiac vagal activity, and (iii) during acute and chronic psychosocial stress challenges, and analyzed via time- and frequency-domain analysis of heart rate variability. Npy1rrfb mice showed a lower Npy1r mRNA density in the dentate gyrus and in the CA1 region of the hippocampus. Under resting undisturbed conditions, Npy1rrfb mice exhibited (i) a higher heart rate, (ii) a reduced overall heart rate variability, and (iii) lower values of the indices of vagal modulation compared to Npy1r2lox counterparts. Following pharmacological vagal inhibition, heart rate was higher in control but not in Npy1rrfb mice compared to their respective baseline values, suggesting that tonic vagal influences on heart rate were reduced in Npy1rrfb mice. The magnitude of the heart rate response to acute stressors was smaller in Npy1rrfb mice compared to Npy1r2lox counterparts, likely due to a concurrent lower vagal withdrawal. These findings suggest that reduced Y1R expression leads to a decrease in resting vagal modulation and heart rate variability, which, in turn, may determine a reduced cardiac autonomic responsiveness to acute stress challenges.

Pharmacological and genetic studies have shown that the Y1 receptor (Y1R) 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 Y1R gene expression in the hypothalamus of lean and obese Y1R/LacZ transgenic mice (TgY1R/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 (TgY1R/LacZ+/+) and obese (TgY1R/LacZob/ob) mice induced a significant decrease of body weight in both sexes and genotypes. In males, leptin administration decreased β-galactosidase activity in the PVN and DMH of lean mice, and increased transgene expression in the same hypothalamic nuclei of obese mice. Sex-related differences were also observed in both genotypes, since leptin treatment failed to affect transgene expression in hypothalamus of lean and obese female mice. These results provide further evidence for a sexual dimorphism of the hypothalamic NPY-Y1R-mediated pathway in response to changes in leptin circulating levels.

Tributyltin (TBT), a pesticide used in antifouling paints, is toxic for aquatic invertebrates. In vertebrates, TBT may act in obesogen- inducing adipogenetic gene transcription for adipocyte differentiation. In a previous study, we demonstrated that acute administration of TBT induces c-fos expression in the arcuate nucleus. Therefore, in this study, we tested the hypothesis that adult exposure to TBT may alter a part of the nervous pathways controlling animal food intake. In particular, we investigated the expression of neuropeptide Y (NPY) immunoreactivity. This neuropeptide forms neural circuits dedicated to food assumption and its action is mediated by Y1 receptors that are widely expressed in the hypothalamic nuclei responsible for the regulation of food intake and energy homeostasis. To this purpose, TBT was orally administered at a dose of 0.025 mg/kg/day/body weight to adult animals [male and female C57BL/6 (Y1-LacZ transgenic mice] for 4 weeks. No differences were found in body weight and fat deposition, but we observed a significant increase in feed efficiency in TBT-treated male mice and a significant decrease in circulating leptin in both sexes. Computerized quantitative analysis of NPY immunoreactivity and Y1-related β-galactosidase activity demonstrated a statistically significant reduction in NPY and Y1 transgene expression in the hypothalamic circuit controlling food intake of treated male mice in comparison with controls. In conclusion, the present results indicate that adult exposure to TBT is profoundly interfering with the nervous circuits involved in the stimulation of food intake.

Herein, we evaluated whether Placental Mesenchymal Stromal Cells (PDMSCs) derived from normal and Preeclamptic (PE) placentae presented differences in the expression of G1/S-phase regulators p16INK4A, p18INK4C, CDK4 and CDK6. Finally, we investigated normal and PE-PDMSCs paracrine effects on JunB, Cyclin D1, p16INK4A, p18INK4C, CDK4 and CDK6 expressions in physiological term villous explants.PDMSCs were isolated from physiological (n = 20) and PE (n = 24) placentae. Passage three normal and PE-PDMSC and conditioned media (CM) were collected after 48h. Physiological villous explants (n = 60) were treated for 72h with normal or PE-PDMSCs CM. Explants viability was assessed by Lactate Dehydrogenase Cytotoxicity assay. Cyclin D1 localization was evaluated by Immuofluorescence (IF) while JunB, Cyclin-D1 p16INK4A, p18INK4C, CDK4 and CDK6 levels were assessed by Real Time PCR and Western Blot assay.We reported significantly increased p16INK4A and p18INK4C expression in PE- relative to normal PDMSCs while no differences in CDK4 and CDK6 levels were detected. Explants viability was not affected by normal or PE-PDMSCs CM. Normal PDMSCs CM increased JunB, p16INK4 and p18INK4C and decreased Cyclin-D1 in placental tissues. In contrast, PE-PDMSCs CM induced JunB downregulation and Cyclin D1 increase in placental explants. Cyclin D1 IF staining showed that CM treatment targeted mainly the syncytiotrophoblast.We showed Cyclin D1-p16INK4A/p18INK4C altered pathway in PE-PDMSCs demonstrating an aberrant G1/S phase transition in these pathological cells. The abnormal Cyclin D1-p16INK4A/p18INK4C expression in explants conditioned by PE-PDMSCs media suggest a key contribution of mesenchymal cells to the altered trophoblast cell cycle regulation typical of PE pregnancies with fetal-placental compromise.

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. group-housing) as a model. We demonstrated that control Npy1r(2lox) male mice housed in groups show increased anxiety and hypothalamus-pituitary-adrenocortical axis activity compared with Npy1r(2lox) mice isolated for six weeks immediately after weaning. Conversely, Npy1r(Y5R-/-) conditional mutants display an anxious-like behavior but no changes in hypothalamus-pituitary-adrenocortical axis activity as compared with their control littermates, independently of housing conditions. These results suggest that group housing constitutes a mild social stress for our B6129S mouse strain and they confirm that the conditional inactivation of Y1 receptors specifically in Y5 receptor containing neurons increases stress-related anxiety without affecting endocrine stress responses.