RESUMO
During postnatal life, the adipocyte-derived hormone leptin is required for proper targeting of neural inputs to the paraventricular nucleus of the hypothalamus (PVH) and impacts the activity of neurons containing agouti-related peptide (AgRP) in the arcuate nucleus of the hypothalamus. Activity-dependent developmental mechanisms are known to play a defining role during postnatal organization of neural circuits, but whether leptin-mediated postnatal neuronal activity specifies neural projections to the PVH or impacts downstream connectivity is largely unexplored. Here, we blocked neuronal activity of AgRP neurons during a discrete postnatal period and evaluated development of AgRP inputs to defined regions in the PVH, as well as descending projections from PVH oxytocin neurons to the dorsal vagal complex (DVC) and assessed their dependence on leptin or postnatal AgRP neuronal activity. In leptin-deficient mice, AgRP inputs to PVH neurons were significantly reduced, as well as oxytocin-specific neuronal targeting by AgRP. Moreover, downstream oxytocin projections from the PVH to the DVC were also impaired, despite the lack of leptin receptors found on PVH oxytocin neurons. Blocking AgRP neuron activity specifically during early postnatal life reduced the density of AgRP inputs to the PVH, as well as the density of projections from PVH oxytocin neurons to the DVC, and these innervation deficits were associated with dysregulated autonomic function. These findings suggest that postnatal targeting of descending PVH oxytocin projections to the DVC requires leptin-mediated AgRP neuronal activity, and represents a novel activity-dependent mechanism for hypothalamic specification of metabolic circuitry, with consequences for autonomic regulation. Significance statement: Hypothalamic neural circuits maintain homeostasis by coordinating endocrine signals with autonomic responses and behavioral outputs to ensure that physiological responses remain in tune with environmental demands. The paraventricular nucleus of the hypothalamus (PVH) plays a central role in metabolic regulation, and the architecture of its neural inputs and axonal projections is a defining feature of how it receives and conveys neuroendocrine information. In adults, leptin regulates multiple aspects of metabolic physiology, but it also functions during development to direct formation of circuits controlling homeostatic functions. Here we demonstrate that leptin acts to specify the input-output architecture of PVH circuits through an activity-dependent, transsynaptic mechanism, which represents a novel means of sculpting neuroendocrine circuitry, with lasting effects on how the brain controls energy balance.
RESUMO
Arginine vasopressin (AVP) and oxytocin (OT) are well-known as neuropeptides that regulate various social behaviors in mammals. However, little is known about their role in mouse female sexual behavior. Thus, we investigated the role of AVP (v1a and v1b) and OT receptors on female sexual behavior. First, we devised a new apparatus, the bilevel chamber, to accurately observe female mouse sexual behavior. This apparatus allowed for a more precisely measurement of lordosis as receptivity and rejection-like behavior (newly defined in this study), a reversed expression of proceptivity. To address our research question, we evaluated female sexual behavior in mice lacking v1a (aKO), v1b (bKO), both v1a and v1b (dKO), and OT (OTRKO) receptors. aKO females showed decreased rejection-like behavior but a normal level of lordosis, whereas bKO females showed almost no lordosis and no change in rejection-like behavior. In addition, dKO females showed normal lordosis levels, suggesting that the v1b receptor promotes lordosis, but not necessarily, while the v1a receptor latently suppresses it. In contrast, although OTRKO did not influence lordosis, it significantly increased rejection-like behavior. In summary, the present results demonstrated that the v1a receptor inhibits proceptivity and receptivity, whereas the v1b and OT receptors facilitate receptivity and proceptivity, respectively.
Assuntos
Camundongos Knockout , Receptores de Ocitocina , Receptores de Vasopressinas , Comportamento Sexual Animal , Animais , Feminino , Receptores de Vasopressinas/metabolismo , Receptores de Vasopressinas/genética , Receptores de Ocitocina/metabolismo , Receptores de Ocitocina/genética , Comportamento Sexual Animal/fisiologia , Camundongos , Masculino , Ocitocina/metabolismo , Camundongos Endogâmicos C57BL , Arginina Vasopressina/metabolismoRESUMO
The high prevalence of obesity has become a pressing global public health problem and there exists a strong association between increased BMI and mortality at a BMI of 25 kg/m2 or higher. The prevalence of obesity is higher among middle-aged adults than among younger groups and the combination of aging and obesity exacerbate systemic inflammation. Increased inflammatory cytokines such as interleukin 6 and tumor necrosis factor alpha (TNFα) are hallmarks of obesity, and promote the secretion of hepatic C-reactive protein (CRP) which further induces systematic inflammation. The neuropeptide oxytocin has been shown to have anti-obesity and anti-inflammation effects, and also suppress sweet-tasting carbohydrate consumption in mammals. Previously, we have shown that the Japanese herbal medicine Kamikihito (KKT), which is used to treat neuropsychological stress disorders in Japan, functions as an oxytocin receptors agonist. In the present study, we further investigated the effect of KKT on body weight (BW), food intake, inflammation, and sweet preferences in middle-aged obese mice. KKT oral administration for 12 days decreased the expression of pro-inflammatory cytokines in the liver, and the plasma CRP and TNFα levels in obese mice. The effect of KKT administration was found to be different between male and female mice. In the absence of sucrose, KKT administration decreased food intake only in male mice. However, while having access to a 30% sucrose solution, both BW and food intake was decreased by KKT administration in male and female mice; but sucrose intake was decreased in female mice alone. In addition, KKT administration decreased sucrose intake in oxytocin deficient lean mice, but not in the WT lean mice. The present study demonstrates that KKT ameliorates chronic inflammation, which is strongly associated with aging and obesity, and decreases food intake in male mice as well as sucrose intake in female mice; in an oxytocin receptor dependent manner.
Assuntos
Dieta Hiperlipídica , Medicamentos de Ervas Chinesas , Inflamação , Camundongos Endogâmicos C57BL , Obesidade , Animais , Obesidade/metabolismo , Obesidade/tratamento farmacológico , Masculino , Camundongos , Dieta Hiperlipídica/efeitos adversos , Inflamação/metabolismo , Feminino , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Sacarose/administração & dosagem , Preferências Alimentares/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Ocitocina/farmacologia , Medicina Kampo , População do Leste AsiáticoRESUMO
INTRODUCTION: GLP-1 receptor agonists are the number one drug prescribed for the treatment of obesity and type 2 diabetes. These drugs are not, however, without side effects, and in an effort to maximize therapeutic effect while minimizing adverse effects, gut hormone co-agonists received considerable attention as new drug targets in the fight against obesity. Numerous previous reports identified the neuropeptide oxytocin (OXT) as a promising anti-obesity drug. The aims of this study were to evaluate OXT as a possible co-agonist for GLP-1 and examine the effects of its co-administration on food intake (FI) and body weight (BW) in mice. METHODS: FI and c-Fos levels were measured in the feeding centers of the brain in response to an intraperitoneal injection of saline, OXT, GLP-1, or OXT/GLP-1. The action potential frequency and cytosolic Ca2+ ([Ca2+]i) in response to OXT, GLP-1, or OXT/GLP-1 were measured in ex vivo paraventricular nucleus (PVN) neuronal cultures. Finally, FI and BW changes were compared in diet-induced obese mice treated with saline, OXT, GLP-1, or OXT/GLP-1 for 13 days. RESULTS: Single injection of OXT/GLP-1 additively decreased FI and increased c-Fos expression specifically in the PVN and supraoptic nucleus. Seventy percent of GLP-1 receptor-positive neurons in the PVN also expressed OXT receptors, and OXT/GLP-1 co-administration dramatically increased firing and [Ca2+]i in the PVN OXT neurons. The chronic OXT/GLP-1 co-administration decreased BW without changing FI. CONCLUSION: Chronic OXT/GLP-1 co-administration decreases BW, possibly via the activation of PVN OXT neurons. OXT might be a promising candidate as an incretin co-agonist in obesity treatment.
Assuntos
Peso Corporal , Ingestão de Alimentos , Peptídeo 1 Semelhante ao Glucagon , Camundongos Endogâmicos C57BL , Ocitocina , Ocitocina/administração & dosagem , Ocitocina/farmacologia , Ocitocina/metabolismo , Animais , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Masculino , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Camundongos , Peso Corporal/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-fos/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismoRESUMO
Antibodies are one of the most utilized tools in biomedical research. However, few of them are rigorously evaluated, as there are no accepted guidelines or standardized methods for determining their validity before commercialization. Often, an antibody is considered validated if it detects a band by Western blot of the expected molecular weight and, in some cases, if blocking peptides result in loss of staining. Neither of these approaches are unquestionable proof of target specificity. Since the oxytocin receptor has recently become a popular target in neuropsychiatric research, the need for specific antibodies to be used in brain has arisen. In this work, we have tested the specificity of six commercially available oxytocin receptor antibodies, indicated by the manufacturers to be suitable for Western blot and with an available image showing the correct size band (45-55 KDa). Antibodies were first tested by Western blot in brain lysates of wild-type and oxytocin receptor knockout mice. Uterus tissue was also tested as control for putative differential tissue specificity. In brain, the six tested antibodies lacked target specificity, as both wild-type and receptor knockout samples resulted in a similar staining pattern, including the expected 45-55 KDa band. Five of the six antibodies detected a selective band in uterus (which disappeared in knockout tissue). These five specific antibodies were also tested for immunohistochemistry in uterus, where only one was specific. However, when the uterine-specific antibody was tested in brain tissue, it lacked specificity. In conclusion, none of the six tested commercial antibodies are suitable to detect oxytocin receptor in brain by either Western blot or immunohistochemistry, although some do specifically detect it in uterus. The present work highlights the need to develop standardized antibody validation methods, including a proper negative control, in order to grant quality and reproducibility of the generated data.
Assuntos
Anticorpos , Receptores de Ocitocina , Animais , Feminino , Camundongos , Western Blotting , Camundongos Knockout , Receptores de Ocitocina/imunologia , Receptores de Ocitocina/metabolismo , Reprodutibilidade dos TestesRESUMO
INTRODUCTION: In nurturing systems, the oxytocin (Oxt)-oxytocin receptor (Oxtr) system is important for parturition, and essential for lactation and parental behavior. Among the nerve nuclei that express Oxtr, the lateral septal nucleus (LS) and medial preoptic area (MPOA) are representative regions that control maternal behavior. METHODS: We investigated the role of Oxtr- and Oxtr-expressing neurons, located in the LS and MPOA, in regulating maternal behavior by regulating Oxtr expression in a region-specific manner using recombinant mice and adeno-associated viruses. We quantified the prolactin (Prl) concentrations in the pituitary gland and plasma when Oxtr expression in the MPOA was reduced. RESULTS: The endogenous Oxtr gene in the neurons of the LS did not seem to play an essential role in maternal behavior. Conversely, decreased Oxtr expression in the MPOA increased the frequency of pups being left outside the nest and reduced their survival rate. Deletion of Oxtr in MPOA neurons prevented elevation of Prl levels in plasma and pituitary at postpartum day 2. DISCUSSION/CONCLUSION: Oxtr-expressing neurons in the MPOA are involved in the postpartum production of Prl. We confirmed the essential functions of Oxtr-expressing neurons and the Oxtr gene itself in the MPOA for the sustainability of maternal behavior, which involved Oxtr-dependent induction of Prl.
RESUMO
Maternal care is crucial for the survival and development of offspring. Oxytocin modulates maternal behavior by binding to oxytocin receptors (OXTRs) in various parts of the brain. Previously, we showed that OXTRs are expressed in the anteroventral periventricular nucleus (AVPV) of female, but not male mice. Because the AVPV is involved in the regulation of maternal behavior and oxytocin enhances its induction, this finding leads to the hypothesis that the female specific population of OXTR neurons in the AVPV regulates maternal behavior. To address this hypothesis, OXTR-Venus reporter mice were used to assess if expression levels of OXTR in the AVPV are changed during the postpartum period. The total number of OXTR-Venus neurons was significantly greater in postpartum dams compared to virgin females. To assess efferent projections of the AVPV-OXTR neurons, a Cre-dependent fluorescent protein (tdTomato) expressing a viral vector was injected into one side of the AVPV of female OXTR-Cre mice. Fibers expressing tdTomato were found in hypothalamic areas containing oxytocin neurons (the supraoptic and paraventricular nuclei) and the midbrain areas (the ventral tegmental area and periaqueductal gray) that are involved in the regulation of maternal motivation. To assess if activity of the AVPV-OXTR neurons is involved in the regulation of maternal behaviors, a chemogenetic approach was employed. Specific inhibition of activity of AVPV-OXTR neurons completely abolished pup retrieval and nest building behaviors. Collectively, these findings demonstrate that AVPV-OXTR neurons in postpartum female mice constitute an important node in the neural circuitry that regulates maternal behavior.
Assuntos
Ocitocina , Receptores de Ocitocina , Animais , Feminino , Humanos , Camundongos , Hipotálamo Anterior/metabolismo , Comportamento Materno/fisiologia , Neurônios/metabolismo , Ocitocina/metabolismo , Período Pós-Parto , Receptores de Ocitocina/genética , Receptores de Ocitocina/metabolismo , Caracteres SexuaisRESUMO
SIGNIFICANCE STATEMENT: Nuclear translocation of dendrin is observed in injured podocytes, but the mechanism and its consequence are unknown. In nephropathy mouse models, dendrin ablation attenuates proteinuria, podocyte loss, and glomerulosclerosis. The nuclear translocation of dendrin promotes c-Jun N -terminal kinase phosphorylation in podocytes, altering focal adhesion and enhancing cell detachment-induced apoptosis. We identified mediation of dendrin nuclear translocation by nuclear localization signal 1 (NLS1) sequence and adaptor protein importin- α . Inhibition of importin- α prevents nuclear translocation of dendrin, decreases podocyte loss, and attenuates glomerulosclerosis in nephropathy models. Thus, inhibiting importin- α -mediated nuclear translocation of dendrin is a potential strategy to halt podocyte loss and glomerulosclerosis. BACKGROUND: Nuclear translocation of dendrin is observed in the glomeruli in numerous human renal diseases, but the mechanism remains unknown. This study investigated that mechanism and its consequence in podocytes. METHODS: The effect of dendrin deficiency was studied in adriamycin (ADR) nephropathy model and membrane-associated guanylate kinase inverted 2 ( MAGI2 ) podocyte-specific knockout ( MAGI2 podKO) mice. The mechanism and the effect of nuclear translocation of dendrin were studied in podocytes overexpressing full-length dendrin and nuclear localization signal 1-deleted dendrin. Ivermectin was used to inhibit importin- α . RESULTS: Dendrin ablation reduced albuminuria, podocyte loss, and glomerulosclerosis in ADR-induced nephropathy and MAGI2 podKO mice. Dendrin deficiency also prolonged the lifespan of MAGI2 podKO mice. Nuclear dendrin promoted c-Jun N -terminal kinase phosphorylation that subsequently altered focal adhesion, reducing cell attachment and enhancing apoptosis in cultured podocytes. Classical bipartite nuclear localization signal sequence and importin- α mediate nuclear translocation of dendrin. The inhibition of importin- α / ß reduced dendrin nuclear translocation and apoptosis in vitro as well as albuminuria, podocyte loss, and glomerulosclerosis in ADR-induced nephropathy and MAGI2 podKO mice. Importin- α 3 colocalized with nuclear dendrin in the glomeruli of FSGS and IgA nephropathy patients. CONCLUSIONS: Nuclear translocation of dendrin promotes cell detachment-induced apoptosis in podocytes. Therefore, inhibiting importin- α -mediated dendrin nuclear translocation is a potential strategy to prevent podocyte loss and glomerulosclerosis.
Assuntos
Glomerulonefrite por IGA , Glomerulosclerose Segmentar e Focal , Podócitos , Humanos , Camundongos , Animais , Podócitos/metabolismo , Albuminúria/metabolismo , alfa Carioferinas/metabolismo , Sinais de Localização Nuclear/metabolismo , Doxorrubicina/metabolismo , Glomerulonefrite por IGA/metabolismo , Glomerulosclerose Segmentar e Focal/metabolismoRESUMO
Decades of studies have revealed molecular and neural circuit bases for body weight homeostasis. Neural hormone oxytocin (Oxt) has received attention in this context because it is produced by neurons in the paraventricular hypothalamic nucleus (PVH), a known output center of hypothalamic regulation of appetite. Oxt has an anorexigenic effect, as shown in human studies, and can mediate satiety signals in rodents. However, the function of Oxt signaling in the physiological regulation of appetite has remained in question, because whole-body knockout (KO) of Oxt or Oxt receptor (Oxtr) has little effect on food intake. We herein show that acute conditional KO (cKO) of Oxt selectively in the adult PVH, but not in the supraoptic nucleus, markedly increases body weight and food intake, with an elevated level of plasma triglyceride and leptin. Intraperitoneal administration of Oxt rescues the hyperphagic phenotype of the PVH Oxt cKO model. Furthermore, we show that cKO of Oxtr selectively in the posterior hypothalamic regions, especially the arcuate hypothalamic nucleus, a primary center for appetite regulations, phenocopies hyperphagic obesity. Collectively, these data reveal that Oxt signaling in the arcuate nucleus suppresses excessive food intake.
Assuntos
Leptina , Ocitocina , Humanos , Camundongos , Animais , Hiperfagia , Obesidade/genética , Núcleo Hipotalâmico Paraventricular , Peso Corporal , Hipotálamo , Hipotálamo Posterior , TriglicerídeosRESUMO
BACKGROUND: Oxytocin is a neuropeptide synthesized in the hypothalamus. In addition to its role in parturition and lactation, oxytocin mediates social behavior and pair bonding. The possibility of using oxytocin to modify behavior in neurodevelopmental disorders, such as autism spectrum disorder, is of clinical interest. Microglia are tissue-resident macrophages with roles in neurogenesis, synapse pruning, and immunological mediation of brain homeostasis. Recently, oxytocin was found to attenuate microglial secretion of proinflammatory cytokines, but the source of this oxytocin was not established. This prompted us to investigate whether microglia themselves were the source. METHODS: We examined oxytocin expression in human and murine brain tissue in both sexes using immunohistochemistry. Oxytocin mRNA expression and secretion were examined in isolated murine microglia from wild type and oxytocin-knockout mice. Also, secretion of oxytocin and cytokines was measured in cultured microglia (MG6) stimulated with lipopolysaccharide (LPS). RESULTS: We identified oxytocin expression in microglia of human brain tissue, cultured microglia (MG6), and primary murine microglia. Furthermore, LPS stimulation increased oxytocin mRNA expression in primary murine microglia and MG6 cells, and oxytocin secretion as well. A positive correlation between oxytocin and IL-1ß, IL-10 secretion emerged, respectively. CONCLUSION: This may be the first demonstration of oxytocin expression in microglia. Functionally, oxytocin might regulate inflammatory cytokine release from microglia in a paracrine/autocrine manner.
Assuntos
Transtorno do Espectro Autista , Microglia , Animais , Transtorno do Espectro Autista/metabolismo , Células Cultivadas , Citocinas/metabolismo , Feminino , Humanos , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Camundongos Knockout , Microglia/metabolismo , Ocitocina/metabolismo , RNA Mensageiro/metabolismoRESUMO
Several studies suggest that rodents show empathic responses and helping behavior toward others. We examined whether prairie voles would help conspecifics who were soaked in water by opening a door to a safe area. Door-opening latency decreased as task sessions progressed. Female and male voles stayed close to the soaked voles' side at equal rates and opened the door with similar latencies. When the conspecific was not soaked in water, the door-opening latency did not decrease. This suggests that the distress of the conspecific is necessary for learning to open the door and that the door-opening performed by prairie voles corresponds to helping behavior. Additionally, we examined the helping behavior in prairie voles in which oxytocin receptors were genetically knocked out. Oxytocin receptor knockout voles demonstrated less learning of the door-opening behavior and less interest in soaked conspecifics. This suggests that oxytocin is important for the emergence of helping behavior.
RESUMO
Oxytocin (Oxt) controls reproductive physiology and various kinds of social behaviors, but the exact contribution of Oxt to different components of parental care still needs to be determined. Here, we illustrate the neuroanatomical relations of the parental nurturing-induced neuronal activation with magnocellular Oxt neurons and fibers in the medial preoptic area (MPOA), the brain region critical for parental and alloparental behaviors. We used genetically-targeted mouse lines for Oxt, Oxt receptor (Oxtr), vasopressin receptor 1a (Avpr1a), vasopressin receptor 1b (Avpr1b), and thyrotropin-releasing hormone (Trh) to systematically examine the role of Oxt-related signaling in pup-directed behaviors. The Oxtr-Avpr1a-Avpr1b triple knock-out (TKO), and Oxt-Trh-Avpr1a-Avpr1b quadruple KO (QKO) mice were grossly healthy and fertile, except for their complete deficiency in milk ejection and modest deficiency in parturition secondary to maternal loss of the Oxt or Oxtr gene. In our minimal stress conditions, pup-directed behaviors in TKO and QKO mothers and fathers, virgin females and males were essentially indistinguishable from those of their littermates with other genotypes. However, Oxtr KO virgin females did show decreased pup retrieval in the pup-exposure assay performed right after restraint stress. This stress vulnerability in the Oxtr KO was abolished by the additional Avpr1b KO. The general stress sensitivity, as measured by plasma cortisol elevation after restraint stress or by the behavioral performance in the open field (OF) and elevated plus maze (EPM), were not altered in the Oxtr KO but were reduced in the Avpr1b KO females, indicating that the balance of neurohypophysial hormones affects the outcome of pup-directed behaviors.
Assuntos
Ocitocina , Receptores de Ocitocina , Animais , Feminino , Masculino , Camundongos , Neurônios , Parto , Gravidez , Receptores de Ocitocina/genética , Comportamento SocialRESUMO
The oxytocin receptor (OXTR) knockout mouse is a model of autism spectrum disorder, characterized by abnormalities in social and olfactory behaviors and learning. Previously, we demonstrated that OXTR plays a crucial role in regulating aversive olfactory behavior to butyric acid odor. In this study, we attempted to determine whether coffee aroma affects the abnormal olfactory behavior of OXTR-Venus knock-in heterozygous mice [heterozygous OXTR (±) mice] using a set of behavioral and molecular experiments. Four-week repeated exposures of heterozygous OXTR (±) mice to coffee odor, containing three kairomone alkylpyrazines, rescued the abnormal olfactory behaviors compared with non-exposed wild-type or heterozygous OXTR (±) mice. Increased Oxtr mRNA expression in the olfactory bulb and amygdala coincided with the rescue of abnormal olfactory behaviors. In addition, despite containing the kairomone compounds, both the wild-type and heterozygous OXTR (±) mice exhibited a preference for the coffee odor and exhibited no stress-like increase in the corticotropin-releasing hormone, instead of a kairomone-associated avoidance response. The repeated exposures to the coffee odor did not change oxytocin and estrogen synthetase/receptors as a regulator of the gonadotropic hormone. These data suggest that the rescue of abnormal olfactory behaviors in heterozygous OXTR (±) mice is due to the coffee odor exposure-induced OXTR expression.
RESUMO
Social and prosocial behaviors, including communication, social bonding, and affiliation, parental behaviors, and empathy are key features of a highly social mammalian species. However, the neuronal mechanism in the brain underlying these behaviors remains unclear because of limited information on the social and prosocial behavioral levels in rodent models generally used in behavioral neuroscience studies.The rodent species, prairie vole (Microtus ochrogaster), is one of the nontraditional animal models with several advantages in experimental science over other rodent models, such as mice or rats. Additionally, it demonstrates characteristics advantageous in the study of social and prosocial behaviors, such as monogamous pair bonding behavior, biparental care, and consoling behavior toward partners stressed by aversive foot shock stimulus. Recent studies of prairie voles have highlighted the importance of oxytocin (OXT) and oxytocin receptor (OXTR)-mediated mechanisms in the regulation of these behaviors.Recently, we established assisted reproductive technologies for prairie voles, and successfully and efficiently generated an OXTR gene knockout (KO) prairie vole using Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9 ), a powerful genome editing tool with artificially developed single-strand guide RNAs (sgRNA) and Cas9 endonucleases.Herein, we describe the method for CRISPR /Cas9-mediated generation of OXTR KO prairie vole. This OXTR KO prairie vole can be a valuable tool to understand their unique social and prosocial behaviors and elucidate how the oxytocin system influences or modulates these behaviors in the brain.
Assuntos
Sistemas CRISPR-Cas , Animais , Arvicolinae/genética , Arvicolinae/metabolismo , Edição de Genes , Pradaria , Camundongos , Ocitocina/genética , Ratos , Receptores de Ocitocina/genética , Técnicas de Reprodução Assistida , Comportamento SocialRESUMO
Retinal progenitor cells (RPCs) divide in limited numbers to generate the cells comprising vertebrate retina. The molecular mechanism that leads RPC to the division limit, however, remains elusive. Here, we find that the hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) in an RPC subset by deletion of tuberous sclerosis complex 1 (Tsc1) makes the RPCs arrive at the division limit precociously and produce Müller glia (MG) that degenerate from senescence-associated cell death. We further show the hyperproliferation of Tsc1-deficient RPCs and the degeneration of MG in the mouse retina disappear by concomitant deletion of hypoxia-induced factor 1-alpha (Hif1a), which induces glycolytic gene expression to support mTORC1-induced RPC proliferation. Collectively, our results suggest that, by having mTORC1 constitutively active, an RPC divides and exhausts mitotic capacity faster than neighboring RPCs, and thus produces retinal cells that degenerate with aging-related changes.
Assuntos
Células Ependimogliais/patologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Retina/patologia , Células-Tronco/patologia , Proteína 1 do Complexo Esclerose Tuberosa/genética , Animais , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Mitose , Proteína 1 do Complexo Esclerose Tuberosa/metabolismoRESUMO
Oxytocin is known as a social bonding hormone, but it also functions as an anxiolytic or analgesic neurotransmitter. When oxytocin regulates pain or anxiousness centrally as a neurotransmitter, it is secreted by neurons and directly projected to targeted regions. Although the function of oxytocin at the spinal level is well studied, its effects at the supraspinal level are poorly understood. We aimed to investigate the effect of oxytocin at the supraspinal level in vivo using C57BL/6J (wild-type [WT]), oxytocin-deficient (Oxt-/-), oxytocin receptor-deficient (Oxtr-/-), and oxytocin receptor-Venus (OxtrVenus/+) mice lines. Response thresholds in Oxtr-/- mice in Hargreaves and von-Frey tests were significantly lower than those in WT mice, whereas open field and light/dark tests showed no significant differences. Moreover, response thresholds in Oxt-/- mice were raised to those in WT mice after oxytocin administration. Following the Hargreaves test, we observed the co-localisation of c-fos with Venus or the oxytocin receptor in the periaqueductal gray (PAG), medial amygdala (MeA), and nucleus accumbens (NAc) regions in OxtrVenus/+ mice. Furthermore, in the PAG, MeA, and NAc regions, the co-localisation of oxytocin with c-fos and gamma-aminobutyric acid was much stronger in Oxtr-/- mice than in WT mice. However, following von-Frey test, the same findings were observed only in the MeA and NAc regions. Our results suggest that oxytocin exerts its analgesic effect on painful stimulation via the PAG region and a self-protective effect on unpleasant stimulation via the MeA and NAc regions.
Assuntos
Sistema Nervoso Central/efeitos dos fármacos , Nociceptividade/efeitos dos fármacos , Ocitocina/farmacologia , Animais , Sistema Nervoso Central/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Maternal care, including by non-biological parents, is important for offspring survival1-8. Oxytocin1,2,9-15, which is released by the hypothalamic paraventricular nucleus (PVN), is a critical maternal hormone. In mice, oxytocin enables neuroplasticity in the auditory cortex for maternal recognition of pup distress15. However, it is unclear how initial parental experience promotes hypothalamic signalling and cortical plasticity for reliable maternal care. Here we continuously monitored the behaviour of female virgin mice co-housed with an experienced mother and litter. This documentary approach was synchronized with neural recordings from the virgin PVN, including oxytocin neurons. These cells were activated as virgins were enlisted in maternal care by experienced mothers, who shepherded virgins into the nest and demonstrated pup retrieval. Virgins visually observed maternal retrieval, which activated PVN oxytocin neurons and promoted alloparenting. Thus rodents can acquire maternal behaviour by social transmission, providing a mechanism for adapting the brains of adult caregivers to infant needs via endogenous oxytocin.
Assuntos
Aprendizagem , Comportamento Materno/psicologia , Mães/psicologia , Neurônios/metabolismo , Ocitocina/metabolismo , Núcleo Hipotalâmico Paraventricular/citologia , Abstinência Sexual/psicologia , Ensino , Animais , Feminino , Abrigo para Animais , Tamanho da Ninhada de Vivíparos , Camundongos , Comportamento de Nidação , Plasticidade NeuronalRESUMO
Maternal mammals exhibit heightened motivation to care for offspring, but the underlying neuromolecular mechanisms have yet to be clarified. Here, we report that the calcitonin receptor (Calcr) and its ligand amylin are expressed in distinct neuronal populations in the medial preoptic area (MPOA) and are upregulated in mothers. Calcr+ MPOA neurons activated by parental care project to somatomotor and monoaminergic brainstem nuclei. Retrograde monosynaptic tracing reveals that significant modification of afferents to Calcr+ neurons occurs in mothers. Knockdown of either Calcr or amylin gene expression hampers risk-taking maternal care, and specific silencing of Calcr+ MPOA neurons inhibits nurturing behaviors, while pharmacogenetic activation prevents infanticide in virgin males. These data indicate that Calcr+ MPOA neurons are required for both maternal and allomaternal nurturing behaviors and that upregulation of amylin-Calcr signaling in the MPOA at least partially mediates risk-taking maternal care, possibly via modified connectomics of Calcr+ neurons postpartum.
Assuntos
Comportamento Animal/fisiologia , Comportamento Materno/fisiologia , Área Pré-Óptica/metabolismo , Receptores da Calcitonina/metabolismo , Assunção de Riscos , Transdução de Sinais , Animais , Estrogênios/metabolismo , Feminino , Inativação Gênica , Marcação de Genes , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Lactação , Ligantes , Masculino , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Período Pós-Parto , Prolactina/metabolismo , Sinapses/metabolismo , Regulação para CimaRESUMO
Social contact reduces stress responses in social animals. Mice have been shown to show allogrooming behaviour toward distressed conspecifics. However, the precise neuronal mechanisms underlying allogrooming behaviour remain unclear. In the present study, we examined whether mice show allogrooming behaviour towards distressed conspecifics in a social defeat model and we also determined whether oxytocin receptor-expressing neurons were activated during allogrooming by examining the expression of c-Fos protein, a marker of neurone activation. Mice showed allogrooming behaviour toward socially defeated conspecifics. After allogrooming behaviour, the percentages of oxytocin receptor-expressing neurones expressing c-Fos protein were significantly increased in the anterior olfactory nucleus, cingulate cortex, insular cortex, lateral septum and medial amygdala of female mice, suggesting that oxytocin receptor-expressing neurones in these areas were activated during allogrooming behaviour toward distressed conspecifics. The duration of allogrooming was correlated with the percentages of oxytocin receptor-expressing neurones expressing c-Fos protein in the anterior olfactory nucleus, insular cortex, lateral septum and medial amygdala. In oxytocin receptor-deficient mice, allogrooming behaviour toward socially defeated cage mates was markedly reduced in female mice but not in male mice, indicating the importance of the oxytocin receptor for allogrooming behaviour in female mice toward distressed conspecifics. The results suggest that the oxytocin receptor, possibly in the anterior olfactory nucleus, insular cortex, lateral septum and/or medial amygdala, facilitates allogrooming behaviour toward socially distressed familiar conspecifics in female mice.
RESUMO
Cesarean section (C/S) is one way of delivering babies, and is chosen when mothers or babies are facing problems or life-threatening conditions during pregnancy. Many meta-analyses have suggested an etiological relationship between C/S delivery and autism spectrum disorders (ASDs). However, as a risk factor for ASDs, C/S delivery has not yet been well studied. Because C/S deliveries have been increasing, it is very important to investigate the causal association between C/S and ASDs. Here, using three approaches, we showed experimentally that C/S delivery induced ASD-like traits in offspring mice, and that some of these changes were ameliorated by one-time oxytocin (OXT) treatment. Treatment with OXT receptor antagonists before natural delivery also induced ASD-related behaviors. Moreover, wild-type mice born to OXT-KO dams showed similar changes. Thus, insufficient OXT exposure from dams to offspring during delivery may be a trigger for ASD-related behaviors.