RESUMO
Repetitive bouts of binge drinking can lead to neuroplastic events that alter ethanol's pharmacologic effects and perpetuate excessive consumption. The corticotropin-releasing factor (CRF) system is an example of ethanol-induced neuroadaptations that drive excessive ethanol consumption. Our laboratory has previously shown that CRF antagonist, when infused into the central amygdala (CeA), reduces binge-like ethanol consumption. The present study extends this research by assessing the effects of silencing CRF-producing neurons in CeA on binge-like ethanol drinking stemming from "Drinking in the Dark" (DID) procedures. CRF-ires-Cre mice underwent surgery to infuse Gi/o-coupled Designer Receptors Exclusively Activated by Designer Drugs (DREADD) virus or a control virus into either the CeA or basolateral amygdala (BLA). Gi/o-DREADD-induced CRF-neuronal inhibition in the CeA resulted in a 33% decrease in binge-like ethanol consumption. However, no effect on ethanol consumption was seen after DREADD manipulation in the BLA. Moreover, CeA CRF-neuronal inhibition had no effect on sucrose consumption. The effects of silencing CRF neurons in the CeA on ethanol consumption are not secondary to changes in motor function or anxiety-like behaviors as assessed in the open-field test (OFT). Finally, the DREADD construct's functional ability to inhibit CRF-neuronal activity was demonstrated by reduced ethanol-induced c-Fos following DREADD activation. Together, these data suggest that the CRF neurons in the CeA play an important role in binge ethanol consumption and that inhibition of the CRF-signaling pathway remains a viable target for manipulating binge-like ethanol consumption. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
Assuntos
Núcleo Central da Amígdala , Hormônio Liberador da Corticotropina , Camundongos , Masculino , Animais , Hormônio Liberador da Corticotropina/fisiologia , Camundongos Endogâmicos C57BL , Etanol , NeurôniosRESUMO
Stress impairs the hypothalamic-pituitary-gonadal (HPG) axis, probably through its influence on the hypothalamic-pituitary-adrenal (= interrenals in the teleost, HPI) axis leading to reproductive failures. In this study, we investigated the response of hypothalamic neuropeptides, gonadotropin-inhibitory hormone (GnIH), a component of the HPG axis, and corticotropin-releasing hormone (CRH) a component of the HPI axis, to acute social defeat stress in the socially hierarchical male Nile tilapia (Oreochromis niloticus). Localization of GnIH cell bodies, GnIH neuronal processes, and numbers of GnIH cells in the brain during acute social defeat stress was studied using immunohistochemistry. Furthermore, mRNA levels of GnIH and CRH in the brain together with GnIH receptor, gpr147, and adrenocorticotropic hormone (ACTH) in the pituitary were quantified in control and socially defeated fish. Our results show, the number of GnIH-immunoreactive cell bodies and GnIH mRNA levels in the brain and the levels of gpr147 mRNA in the pituitary significantly increased in socially defeated fish. However, CRH and ACTH mRNA levels did not change during social defeat stress. Further, we found glucocorticoid type 2b receptor mRNA in laser captured immunostained GnIH cells. These results show that acute social defeat stress activates GnIH biosynthesis through glucocorticoid receptors type 2b signalling but does not change the CRH and ACTH mRNA expression in the tilapia, which could lead to temporary reproductive dysfunction.
Assuntos
Hormônio Liberador da Corticotropina/genética , Hormônio Liberador de Gonadotropina/biossíntese , Estresse Psicológico/genética , Tilápia/fisiologia , Hormônio Adrenocorticotrópico/biossíntese , Hormônio Adrenocorticotrópico/fisiologia , Animais , Encéfalo/fisiologia , Hormônio Liberador da Corticotropina/fisiologia , Feminino , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/fisiologia , Gonadotropinas/biossíntese , Gonadotropinas/genética , Masculino , Hipófise/metabolismo , Reprodução/genética , Reprodução/fisiologia , Derrota Social , Tilápia/genéticaRESUMO
Abstract Introduction In addition to their role in regulation of the hypothalamic-pituitary-adrenal-axis, corticotropin-releasing factor (CRF) and its related peptides, the urocortins, are important mediators of physiological and pathophysiological processes of the central nervous, cardiovascular, gastrointestinal, immune, endocrine, reproductive, and skin systems. Altered regulation of CRF-mediated adaptive responses to various stressful stimuli disrupts healthy function and might confer vulnerability to several disorders, including depression and anxiety. Methodology This narrative review was conducted through search and analysis of studies retrieved from online databases using a snowball method. Results This review covers aspects beginning with the discovery of CRF, CRF binding protein and their actions via interaction with CRF receptors type 1 and type 2. These are surface plasma membrane receptors, activation of which is associated with conformational changes and interaction with a variety of G-proteins and signaling pathways. We also reviewed the pharmacology and mechanisms of the receptor signaling modulatory activity of these receptors. Conclusion This review compiles and presents knowledge regarding the CRFergic system, including CRF related peptides, CRF binding protein, and CRF receptors, as well as some evidence that is potentially indicative of the biological roles of these entities in several physiological and pathophysiological processes.
Assuntos
Animais , Humanos , Estresse Psicológico/metabolismo , Hormônio Liberador da Corticotropina/fisiologia , Transdução de Sinais/fisiologia , Receptores de Hormônio Liberador da Corticotropina/fisiologia , Sistema Hipotálamo-Hipofisário/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Receptores de Hormônio Liberador da Corticotropina/metabolismoRESUMO
The bed nucleus of the stria terminalis (BNST) is a forebrain region highly responsive to stress that expresses corticotropin-releasing hormone (CRH) and is implicated in mood disorders, such as anxiety. However, the exact mechanism by which chronic stress induces CRH-mediated dysfunction in BNST and maladaptive behaviors remains unclear. Here, we first confirmed that selective acute optogenetic activation of the oval nucleus BNST (ovBNST) increases maladaptive avoidance behaviors in male mice. Next, we found that a 6 week chronic variable mild stress (CVMS) paradigm resulted in maladaptive behaviors and increased cellular excitability of ovBNST CRH neurons by potentiating mEPSC amplitude, altering the resting membrane potential, and diminishing M-currents (a voltage-gated K+ current that stabilizes membrane potential) in ex vivo slices. CVMS also increased c-fos+ cells in ovBNST following handling. We next investigated potential molecular mechanism underlying the electrophysiological effects and observed that CVMS increased CRH+ and pituitary adenylate cyclase-activating polypeptide+ (PACAP; a CRH upstream regulator) cells but decreased striatal-enriched protein tyrosine phosphatase+ (a STEP CRH inhibitor) cells in ovBNST. Interestingly, the electrophysiological effects of CVMS were reversed by CRHR1-selective antagonist R121919 application. CVMS also activated protein kinase A (PKA) in BNST, and chronic infusion of the PKA-selective antagonist H89 into ovBNST reversed the effects of CVMS. Coadministration of the PKA agonist forskolin prevented the beneficial effects of R121919. Finally, CVMS induced an increase in surface expression of phosphorylated GluR1 (S845) in BNST. Collectively, these findings highlight a novel and indispensable stress-induced role for PKA-dependent CRHR1 signaling in activating BNST CRH neurons and mediating maladaptive behaviors.SIGNIFICANCE STATEMENT Chronic stress and acute activation of oval bed nucleus of the stria terminalis (ovBNST) induces maladaptive behaviors in rodents. However, the precise molecular and electrophysiological mechanisms underlying these effects remain unclear. Here, we demonstrate that chronic variable mild stress activates corticotropin-releasing hormone (CRH)-associated stress signaling and CRH neurons in ovBNST by potentiating mEPSC amplitude and decreasing M-current in male mice. These electrophysiological alterations and maladaptive behaviors were mediated by BNST protein kinase A-dependent CRHR1 signaling. Our results thus highlight the importance of BNST CRH dysfunction in chronic stress-induced disorders.
Assuntos
Adaptação Psicológica , Hormônio Liberador da Corticotropina/fisiologia , Núcleos Septais/fisiologia , Transdução de Sinais/fisiologia , Estresse Psicológico/psicologia , Animais , Doença Crônica , Hormônio Liberador da Corticotropina/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Fenômenos Eletrofisiológicos/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Genes fos , Masculino , Potenciais da Membrana/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Polipeptídeo Hipofisário Ativador de Adenilato Ciclase/metabolismo , Canais de Potássio/fisiologia , Proteínas Tirosina Fosfatases/metabolismo , Receptores de Hormônio Liberador da Corticotropina/antagonistas & inibidoresRESUMO
CRF system is comprised of 4 homologous lineages, 2 main receptors (CRF-R1 and CRF-R2), and a binding protein CRF-BP. The homologous lineages are corticotropin-releasing factor (CRF), urotensin I (UI)/sauvagine (SVG)/urocortin 1 (UCN1), urocortin 2 (UCN2), and urocortin 3 (UCN3), and UI, SVG, UCN1 are orthologous genes. CRF system genes are widely distributed in the brain and gastrointestinal tract, which may relate to feeding regulation. According the research progress about CRF system on mammals and non-mammals, this paper summarized the discovery, structure, tissue distribution, appetite regulation and mechanism of CRF system in animals, which can provide the reference for further research and production of feeding regulation and growth in mammals and fish species.
Assuntos
Apetite/genética , Hormônio Liberador da Corticotropina/metabolismo , Hormônio Liberador da Corticotropina/fisiologia , Proteínas de Anfíbios , Animais , Encéfalo/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Hormônio Liberador da Corticotropina/genética , Comportamento Alimentar/fisiologia , Hormônios Peptídicos , Urocortinas , UrotensinasRESUMO
Stress contributes to numerous psychiatric disorders. Corticotropin releasing factor (CRF) signaling and CRF neurons in the bed nucleus of the stria terminalis (BNST) drive negative affective behaviors, thus agents that decrease activity of these cells may be of therapeutic interest. Here, we show that acute restraint stress increases cFos expression in CRF neurons in the mouse dorsal BNST, consistent with a role for these neurons in stress-related behaviors. We find that activation of α2A-adrenergic receptors (ARs) by the agonist guanfacine reduced cFos expression in these neurons both in stressed and unstressed conditions. Further, we find that α- and ß-ARs differentially regulate excitatory drive onto these neurons. Pharmacological and channelrhodopsin-assisted mapping experiments suggest that α2A-ARs specifically reduce excitatory drive from parabrachial nucleus (PBN) afferents onto CRF neurons. Given that the α2A-AR is a Gi-linked GPCR, we assessed the impact of activating the Gi-coupled DREADD hM4Di in the PBN on restraint stress regulation of BNST CRF neurons. CNO activation of PBN hM4Di reduced stress-induced Fos in BNST Crh neurons. Further, using Prkcd as an additional marker of BNST neuronal identity, we uncovered a female-specific upregulation of the coexpression of Prkcd/Crh in BNST neurons following stress, which was prevented by ovariectomy. These findings show that stress activates BNST CRF neurons, and that α2A-AR activation suppresses the in vivo activity of these cells, at least in part by suppressing excitatory drive from PBN inputs onto CRF neurons.SIGNIFICANCE STATEMENT Stress is a major variable contributing to mood disorders. Here, we show that stress increases activation of BNST CRF neurons that drive negative affective behavior. We find that the clinically well tolerated α2A-AR agonist guanfacine reduces activity of these cells in vivo, and reduces excitatory PBN inputs onto these cells ex vivo Additionally, we uncover a novel sex-dependent coexpression of Prkcd with Crh in female BNST neurons after stress, an effect abolished by ovariectomy. These results demonstrate input-specific interactions between norepinephrine and CRF, and point to an action by which guanfacine may reduce negative affective responses.
Assuntos
Agonistas de Receptores Adrenérgicos alfa 2/farmacologia , Hormônio Liberador da Corticotropina/fisiologia , Neurônios/fisiologia , Núcleos Parabraquiais/efeitos dos fármacos , Receptores Adrenérgicos alfa 2/efeitos dos fármacos , Núcleos Septais/efeitos dos fármacos , Animais , Feminino , Expressão Gênica/efeitos dos fármacos , Genes fos/efeitos dos fármacos , Guanfacina/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Norepinefrina/farmacologia , Ovariectomia , Técnicas de Patch-Clamp , Proteína Quinase C-delta/efeitos dos fármacos , Receptores Acoplados a Proteínas G/efeitos dos fármacos , Restrição Física , Estresse Psicológico/fisiopatologiaRESUMO
Vasoactive intestinal peptide (VIP) and corticotrophin-releasing factor (CRF) are anorexigenic neuropeptides that act in the hypothalamus to regulate food intake. Intracerebroventricular (ICV) microinjection of VIP promotes increased plasma adrenocorticotrophic hormone (ACTH) and corticosterone, indicating that VIP activates hypothalamic-pituitary-adrenal axis. The aim of this study was to evaluate the interaction between VIP and CRF, by verifying the effects of ICV administration of VIP on the activity of neurons and CRF mRNA expression in paraventricular nucleus of hypothalamus (PVN). In addition, it was evaluated the effects of pretreatment with CRF type 1 receptor (CRFR1) antagonist (Antalarmin, ANT) or CRF type 2 receptor (CRFR2) antagonist (Antisauvagine-30, AS30) on VIP-induced changes on food intake and plasma parameters of male rats. Compared to Saline group, VIP increased not only the number of Fos-related antigens (FRA)-immunoreactive neurons in the PVN but also CRF mRNA levels in this nucleus. Both ANT and AS30 treatment attenuated the inhibition of food intake promoted by VIP, ANT showing a more pronounced effect. Both antagonists also attenuated VIP-induced reduction and enhancement of free fatty acids and corticosterone plasma levels, respectively, and only AS30 was able to attenuate the hyperglycemia. These results suggest that CRF is an important mediador of VIP effects on energy balance, and CRFR1 and CRFR2 are involved in these responses.
Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Transtornos da Alimentação e da Ingestão de Alimentos/sangue , Transtornos da Alimentação e da Ingestão de Alimentos/induzido quimicamente , Peptídeo Intestinal Vasoativo/efeitos adversos , Hormônio Adrenocorticotrópico/sangue , Animais , Glicemia/efeitos dos fármacos , Glicemia/metabolismo , Corticosterona/sangue , Hormônio Liberador da Corticotropina/genética , Hormônio Liberador da Corticotropina/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Ácidos Graxos/sangue , Transtornos da Alimentação e da Ingestão de Alimentos/genética , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Hipotálamo/metabolismo , Masculino , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Sistema Hipófise-Suprarrenal/metabolismo , Ratos , Ratos Wistar , Peptídeo Intestinal Vasoativo/metabolismoRESUMO
BACKGROUND: Nicotine addiction supports tobacco smoking, a main preventable cause of disease and death in Western countries. It develops through long-term neuroadaptations in the brain reward circuit by modulating intracellular pathways and regulating gene expression. This study assesses the regional expression of the transcripts of the CRF transmission in a nicotine sensitization model, since it is hypothesised that the molecular neuroadaptations that mediate the development of sensitization contribute to the development of addiction. METHODS: Rats received intraperitoneal nicotine administrations (0.4â¯mg/kg) once daily for either 1 day or over 5 days. Locomotor activity was assessed to evaluate the development of sensitization. The mRNA expression of CRF and CRF1 and CRF2 receptors was measured by qPCR in the ventral mesencephalon, ventral striatum, dorsal striatum (DS), prefrontal cortex (PFCx), and hippocampus (Hip). RESULTS: Acute nicotine administration increased locomotor activity in rats. In the sub-chronic group, locomotor activity progressively increased and reached a clear sensitization. Significant effects of sensitization on CRF mRNA levels were detected in the DS (increasing effect). Significantly higher CRF1 and CRF2 receptor levels after sensitization were detected in the Hip. Additionally, CRF2 receptor levels were augmented by sensitization in the PFCx, and treatment and time-induced increases were detected in the DS. Nicotine treatment effects were observed on CRF1R levels in the DS. CONCLUSIONS: This study suggests that the CRF transmission, in addition to its role in increasing withdrawal-related anxiety, may be involved in the development of nicotine-habituated behaviours through reduced control of impulses and the aberrant memory plasticity characterising addiction.
Assuntos
Sensibilização do Sistema Nervoso Central/fisiologia , Corpo Estriado/metabolismo , Hormônio Liberador da Corticotropina/fisiologia , Hipocampo/metabolismo , Nicotina/farmacologia , Córtex Pré-Frontal/metabolismo , Receptores de Hormônio Liberador da Corticotropina/fisiologia , Animais , Hormônio Liberador da Corticotropina/biossíntese , Locomoção/efeitos dos fármacos , Masculino , Ratos , Receptores de Hormônio Liberador da Corticotropina/biossíntese , RecompensaRESUMO
Glucagon-like Peptide 1 (GLP-1)-expressing neurons in the hindbrain send robust projections to the paraventricular nucleus of the hypothalamus (PVN), which is involved in the regulation of food intake. Here, we describe that stimulation of GLP-1 afferent fibers within the PVN is sufficient to suppress food intake independent of glutamate release. We also show that GLP-1 receptor (GLP-1R) activation augments excitatory synaptic strength in PVN corticotropin-releasing hormone (CRH) neurons, with GLP-1R activation promoting a protein kinase A (PKA)-dependent signaling cascade leading to phosphorylation of serine S845 on GluA1 AMPA receptors and their trafficking to the plasma membrane. Finally, we show that postnatal depletion of GLP-1R in the PVN increases food intake and causes obesity. This study provides a comprehensive multi-level (circuit, synaptic, and molecular) explanation of how food intake behavior and body weight are regulated by endogenous central GLP-1. VIDEO ABSTRACT.
Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Ingestão de Alimentos/fisiologia , Peptídeo 1 Semelhante ao Glucagon/fisiologia , Núcleo Hipotalâmico Paraventricular/fisiologia , Receptores de AMPA/fisiologia , Animais , Células Cultivadas , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Receptor do Peptídeo Semelhante ao Glucagon 1/fisiologia , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/fisiologia , Fosforilação , Receptores de AMPA/metabolismo , Transdução de Sinais/fisiologiaRESUMO
BACKGROUND AND AIM: Repeated water avoidance stress (WAS) induces visceral hypersensitivity. Additionally, it is also known to activate corticotropin-releasing factor (CRF), mast cells, and pro-inflammatory cytokines systems, but their precise roles on visceral sensation have not been determined definitely. The aim of the study was to explore this issue. METHODS: Abdominal muscle contractions induced by colonic balloon distention, that is, visceromotor response (VMR) was detected electrophysiologically in conscious rats. WAS or sham stress as control for 1 h daily was loaded, and the threshold of VMR was determined before and at 24 h after the stress. RESULTS: Repeated WAS for three consecutive days reduced the threshold of VMR, but sham stress did not induce any change. Astressin, a CRF receptor antagonist (50 µg/kg) intraperitoneally (ip) at 10 min before each WAS session, prevented the visceral allodynia, but the antagonist (200 µg/kg) ip at 30 min and 15 h before measurement of the threshold after completing 3-day stress session did not modify the response. Ketotifen, a mast cell stabilizer (3 mg/kg), anakinra, an interleukin (IL)-1 receptor antagonist (20 mg/kg) or IL-6 antibody (16.6 µg/kg) ip for two times before the measurement abolished the response. CONCLUSIONS: Repeated WAS for three consecutive days induced visceral allodynia, which was mediated through mast cells, IL-1, and IL-6 pathways. Inhibition of peripheral CRF signaling prevented but did not reverse this response, suggesting that peripheral CRF may be an essential trigger but may not contribute to the maintenance of repeated WAS-induced visceral allodynia.
Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Hiperalgesia/etiologia , Interleucina-1/fisiologia , Interleucina-6/fisiologia , Transdução de Sinais/fisiologia , Estresse Psicológico/complicações , Vísceras , Músculos Abdominais/fisiopatologia , Animais , Modelos Animais de Doenças , Hiperalgesia/fisiopatologia , Masculino , Mastócitos , Contração Muscular , Ratos Sprague-DawleyRESUMO
BACKGROUND: The neuropeptides vasopressin and corticotropin-releasing factor facilitate, while serotonin inhibits, aggression. How the brain is wired to coordinate interactions between these functionally opposed neurotransmitters to control behavioral states is poorly understood. METHODS: Pair-bonded male prairie voles (Microtus ochrogaster) were infused with a retrograde tracer, Fluoro-Gold, and tested for affiliation and aggression toward a female partner or novel female subject. Subsequent immunocytochemical experiments examined neuronal activation using Fos and neurochemical/neuroreceptor profiles on brain areas involved in these social behaviors. Finally, a series of behavioral pharmacologic and real-time in vivo brain microdialysis experiments were performed on male prairie voles displaying affiliation or aggression. RESULTS: We localized a subpopulation of excitatory vasopressin neurons in the anterior hypothalamus that may gate corticotropin-releasing factor output from the amygdala to the anterior hypothalamus and then the lateral septum to modulate aggression associated with mate guarding. Conversely, we identified a subset of inhibitory serotonergic projection neurons in the dorsal raphe that project to the anterior hypothalamus and may mediate the spatiotemporal release of neuropeptides and their interactions in modulating aggression and affiliation. CONCLUSIONS: Together, this study establishes the medial extended amygdala as a major neural substrate regulating the switch between positive and negative affective states, wherein several neurochemicals converge and interact to coordinate divergent social behaviors.
Assuntos
Agressão/fisiologia , Encéfalo/fisiologia , Hormônio Liberador da Corticotropina/fisiologia , Serotonina/fisiologia , Comportamento Social , Vasopressinas/fisiologia , Tonsila do Cerebelo/metabolismo , Tonsila do Cerebelo/fisiologia , Animais , Arvicolinae , Encéfalo/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Núcleo Dorsal da Rafe/metabolismo , Núcleo Dorsal da Rafe/fisiologia , Feminino , Hipotálamo/metabolismo , Hipotálamo/fisiologia , Masculino , Vias Neurais/metabolismo , Vias Neurais/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Neuropeptídeos/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Receptor 5-HT1A de Serotonina/fisiologia , Núcleos Septais/metabolismo , Núcleos Septais/fisiologia , Neurônios Serotoninérgicos/metabolismo , Neurônios Serotoninérgicos/fisiologia , Serotonina/metabolismo , Vasopressinas/metabolismoRESUMO
While innovative modern neuroscience approaches have aided in discerning brain circuitry underlying negative emotional behaviors including fear and anxiety responses, how these circuits are recruited in normal and pathological conditions remains poorly understood. Recently, genetic tools that selectively manipulate single neuronal populations have uncovered an understudied circuit, the medial habenula (mHb)-interpeduncular (IPN) axis, that modulates basal negative emotional responses. Interestingly, the mHb-IPN pathway also represents an essential circuit that signals heightened anxiety induced by nicotine withdrawal. Insights into how this circuit interconnects with regions more classically associated with anxiety, and how chronic nicotine exposure induces neuroadaptations resulting in an anxiogenic state, may thereby provide novel strategies and molecular targets for therapies that facilitate smoking cessation, as well as for anxiety relief.
Assuntos
Transtornos de Ansiedade/etiologia , Habenula/fisiologia , Núcleo Interpeduncular/fisiologia , Tabagismo/etiologia , Animais , Transtornos de Ansiedade/tratamento farmacológico , Hormônio Liberador da Corticotropina/fisiologia , Emoções , Humanos , Camundongos , Receptores Nicotínicos/fisiologia , Tabagismo/tratamento farmacológico , Área Tegmentar Ventral/fisiologiaRESUMO
Colonic epithelium is the first line of defense against various pathological offenses in the gut. Previous studies have shown that the peptides of the corticotropin-releasing hormone (CRH) family modulate vascular endothelial growth factor (VEGF)-A production in other cells. Here we sought to investigate whether CRH and urocortin (Ucn) 3 regulate VEGF-A secretion in colonocytes through CRH receptors and to elucidate the underlying mechanism of action. CRH and Ucn 3 significantly increased the expression levels of VEGF-A mRNA and protein through CRH receptor 1 and 2, respectively, in human colonic epithelial cells and primary mouse intestinal epithelial cells. Underlying mechanisms involve activation of adenylyl cyclase with subsequent increase of intracellular cAMP level and increased DNA binding activity of transcription factor CREB on VEGF-A promoter region. Finally, genetic deficiency of CREB decreased intestinal inflammation and VEGF-A expression in a dextran sodium sulfate-induced colitis model. These results show that activation of CRH receptors by CRH ligands stimulates VEGF-A expression in intestinal epithelial cells through the cAMP/CREB pathway. Since VEGF-A boosts inflammatory responses through angiogenesis, these data suggest that CREB may be a key effector of CRH and Ucn 3-dependent inflammatory angiogenesis.
Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , AMP Cíclico/metabolismo , Urocortinas/fisiologia , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Células Cultivadas , Humanos , Mucosa Intestinal/citologia , Mucosa Intestinal/metabolismo , Camundongos , Camundongos Transgênicos , Regiões Promotoras Genéticas , Fator A de Crescimento do Endotélio Vascular/genéticaRESUMO
Our group has previously shown that corticotropin releasing factor (CRF) inhibits proliferation of human endocrine-related cancer cell lines via the activation of CRF type-1 receptors (CRF-R1). Tumors originating from the nervous system also express CRF receptors but their role on neoplastic cell proliferation was poorly investigated. Here we investigated the effect of CRF receptor stimulation on nervous system-derived cancer cells, using the SK-N-SH (N) human neuroblastoma cell line as an experimental model. We found that SK-N-SH (N) cells express functionally active CRF-R1, whose activation by CRF and the cognate peptide urocortin (UCN) is associated to reduced cell proliferation and motility, as well as neuronal-like differentiation. UCN did not interfere with cell viability and cell-cycle arrest. Those effects seem to be mediated by a mechanism involving the activation of cAMP/PKA/CREB pathway and the subsequent downstream increase in p27(Kip1) and underphosphorylated retinoblastoma protein levels, as well as reduced c-Myc mRNA accumulation.
Assuntos
Diferenciação Celular , Proliferação de Células , Inibidor de Quinase Dependente de Ciclina p27/fisiologia , Proteínas Proto-Oncogênicas c-myc/metabolismo , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Movimento Celular , Hormônio Liberador da Corticotropina/fisiologia , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica , Humanos , Neuroblastoma , Proteínas Proto-Oncogênicas c-myc/genética , Proteína do Retinoblastoma/metabolismo , Urocortinas/fisiologiaRESUMO
TMEFF2 is a transmembrane protein with unknown function, containing an altered epidermal growth factor (EGF)-like motif, two follistatin-like domains, and a cytosolic tail with a putative G-protein-activating motif. TMEFF2 is predominantly expressed in brain and prostate and has been implicated in cell signaling, neuronal cell survival, and tumor suppression. We found that expression of TMEFF2 in pituitary corticotrope cells inhibits the effects of corticotropin-releasing hormone (CRH) on the production of intracellular cAMP, and CREB, and transcription of Pomc. Regulation of the activity of CRH by TMEFF2 requires neither the cytoplasmic tail nor the EGF domain, while deletion of the follistatin modules abolishes the inhibitory function of TMEFF2. Moreover, a soluble secreted protein containing the complete extracellular domain is sufficient for inhibition of CRH signaling. TMEFF2-induced inhibition depends on serum components. Furthermore, TMEFF2 regulates the non-canonical activin/BMP4 signaling, PI3K, and Ras/ERK1/2 pathways. Thus, TMEFF2 inhibits the CRH signaling pathway and the PI3K/AKT and Ras/ERK1/2 pathways, contributing to a significant inhibition of transcription of Pomc. We found that expression of TMEFF2 in human Cushing's adenoma is reduced when compared with normal human pituitary, which may indicate that TMEFF2 acts as a tumor suppressor in these adenomas. Furthermore, the overexpression of TMEFF2 decreased proliferation of corticotrope cells. Our results indicate a potential therapeutic use of TMEFF2 or factors that stimulate the activity of TMEFF2 for the treatment of corticotrope tumors in order to reduce their secretion of ACTH and proliferation.
Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Proteínas de Membrana/fisiologia , Proteínas de Neoplasias/fisiologia , Hormônio Adrenocorticotrópico/metabolismo , Animais , Proteína Morfogenética Óssea 4/fisiologia , Linhagem Celular Tumoral , Proliferação de Células , AMP Cíclico/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo , Ratos , Sistemas do Segundo Mensageiro , Transcrição GênicaRESUMO
Dopaminergic neurons in the ventral tegmental area (VTA) are well known for mediating the positive reinforcing effects of drugs of abuse. Here we identify in rodents and humans a population of VTA dopaminergic neurons expressing corticotropin-releasing factor (CRF). We provide further evidence in rodents that chronic nicotine exposure upregulates Crh mRNA (encoding CRF) in dopaminergic neurons of the posterior VTA, activates local CRF1 receptors and blocks nicotine-induced activation of transient GABAergic input to dopaminergic neurons. Local downregulation of Crh mRNA and specific pharmacological blockade of CRF1 receptors in the VTA reversed the effect of nicotine on GABAergic input to dopaminergic neurons, prevented the aversive effects of nicotine withdrawal and limited the escalation of nicotine intake. These results link the brain reward and stress systems in the same brain region to signaling of the negative motivational effects of nicotine withdrawal.
Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Neurônios/metabolismo , Nicotina/efeitos adversos , Síndrome de Abstinência a Substâncias/metabolismo , Área Tegmentar Ventral/metabolismo , Animais , Humanos , Potenciais Pós-Sinápticos Inibidores/efeitos dos fármacos , Potenciais Pós-Sinápticos Inibidores/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/efeitos dos fármacos , Técnicas de Cultura de Órgãos , Ratos , Ratos Wistar , Síndrome de Abstinência a Substâncias/psicologia , Área Tegmentar Ventral/efeitos dos fármacosRESUMO
Smoking cessation leads to a dysphoric state and this increases the risk for relapse. Animal studies indicate that the dysphoric state associated with nicotine withdrawal is at least partly mediated by an increase in corticotropin-releasing factor (CRF) release in the central nucleus of the amygdala (CeA). In the present study, we investigated whether a sustained overexpression of CRF in the CeA affects the dysphoric-like state associated with nicotine withdrawal. To study brain reward function, rats were prepared with intracranial self-stimulation (ICSS) electrodes in the medial forebrain bundle. An adeno-associated virus (AAV, pseudotype 2/5) was used to overexpress CRF or green fluorescent protein (GFP, control) in the CeA and minipumps were used to induce nicotine dependence. The AAV2/5-CRF vector induced a 40% increase in CRF protein and mRNA levels in the CeA. Administration of the nicotinic receptor antagonist mecamylamine (precipitated withdrawal) or nicotine pump removal (spontaneous withdrawal) led to elevations in ICSS thresholds. Elevations in ICSS thresholds are indicative of a dysphoric-like state. The overexpression of CRF did not affect baseline ICSS thresholds but diminished the elevations in ICSS thresholds associated with precipitated and spontaneous nicotine withdrawal. The real-time reverse transcriptase (RT)-PCR analysis showed that the overexpression of CRF led to a decrease in CRF1 mRNA levels and an increase in CRF2 mRNA levels in the CeA. In conclusion, the overexpression of CRF in the CeA diminishes the dysphoric-like state associated with nicotine withdrawal and this might be driven by neuroadaptive changes in CRF1 and CRF2 receptor gene expression.
Assuntos
Núcleo Central da Amígdala/metabolismo , Hormônio Liberador da Corticotropina/fisiologia , Nicotina/farmacologia , Receptores de Hormônio Liberador da Corticotropina/biossíntese , Síndrome de Abstinência a Substâncias/metabolismo , Tabagismo/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Hormônio Liberador da Corticotropina/metabolismo , Dependovirus/metabolismo , Masculino , Antagonistas Nicotínicos/administração & dosagem , Antagonistas Nicotínicos/farmacologia , Ratos , Ratos Wistar , Receptores de Hormônio Liberador da Corticotropina/genética , Recompensa , Autoestimulação/efeitos dos fármacosRESUMO
The hypothalamo-pituitary-adrenal (HPA) axis represents a complex neuroendocrine feedback loop controlling the secretion of adrenal glucocorticoid hormones. Central to its function is the paraventricular nucleus of the hypothalamus (PVN) where neurons expressing corticotropin releasing factor reside. These HPA motor neurons are a primary site of integration leading to graded endocrine responses to physical and psychological stressors. An important regulatory factor that must be considered, prior to generating an appropriate response is the animal's reproductive status. Thus, PVN neurons express androgen and estrogen receptors and receive input from sites that also express these receptors. Consequently, changes in reproduction and gonadal steroid levels modulate the stress response and this underlies sex differences in HPA axis function. This review examines the make up of the HPA axis and hypothalamo-pituitary-gonadal (HPG) axis and the interactions between the two that should be considered when exploring normal and pathological responses to environmental stressors.
Assuntos
Hormônio Liberador da Corticotropina/fisiologia , Hormônios Esteroides Gonadais/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Estresse Fisiológico/fisiologia , Animais , Humanos , Receptores de Estrogênio/fisiologiaRESUMO
AAA (abdominal aortic aneurysm) is an important cause of sudden death in older adults, but there is no current effective drug therapy for this disease. The UCNs (urocortins1-3) and their receptors: CRFR (corticotrophin-releasing factor receptor)-1 and -2 have been implicated in various CVDs (cardiovascular diseases). We assessed the relative expression of UCN1-3 in AAA by qRT-PCR (quantitative reverse transcription-PCR) and ELISA, and examined in vitro how UCN2 affects human aortic VSMC (vascular smooth muscle cell) Akt phosphorylation, pro-inflammatory cytokine IL (interleukin)-6 secretion, proliferation, cell cycle and apoptosis. UCN2 and CRFR2 expression were significantly up-regulated in biopsies from the AAA body. AAA body biopsies released high amounts of UCN2 in vitro. Median plasma UCN2 concentrations were 2.20 ng/ml (interquartile range 1.14-4.55 ng/ml, n=67) in AAA patients and 1.11 ng/ml (interquartile range 0.76-2.55 ng/ml, n=67) in patients with non-aneurysmal PAD (peripheral artery disease) (P=0.001). Patients with UCN2 in the highest quartile had a 4.12-fold (95% confidence interval, 1.37-12.40) greater prevalence of AAA independent of other risk factors, P=0.012. In vitro, UCN2 significantly inhibited VSMC Akt phosphorylation and proliferation in a dose-dependent manner. UCN2 induced VSMC G1 cell-cycle arrest and increased IL-6 secretion over 24 h. The CRFR2 antagonist astressin-2B significantly abrogated the effects of UCN2 on VSMCs. In conclusion, UCN2 is significantly associated with AAA and inhibits VSMC proliferation by inducing a G1 cell cycle arrest suggesting a plausible regulatory role in AAA pathogenesis.
Assuntos
Aneurisma da Aorta Abdominal/fisiopatologia , Hormônio Liberador da Corticotropina/fisiologia , Músculo Liso Vascular/patologia , Receptores de Hormônio Liberador da Corticotropina/fisiologia , Urocortinas/fisiologia , Proliferação de Células , Células Cultivadas , Hormônio Liberador da Corticotropina/sangue , Humanos , Interleucina-8/metabolismo , Músculo Liso Vascular/enzimologia , Músculo Liso Vascular/metabolismo , Fosforilação , Proteínas Proto-Oncogênicas c-akt/metabolismo , Urocortinas/sangueRESUMO
We currently face an alarming resurgence in infectious diseases characterized by antimicrobial resistance and therapeutic failure. This has generated the urgent need of developing new therapeutic approaches that include agents with nontraditional modes of action. A recent interest focused on approaches based on our natural immune defenses, especially on peptides that combine innate antimicrobial activity against diverse pathogens and immunoregulatory functions. In this study, to our knowledge, we describe for the first time the antimicrobial activity of the neuropeptide urocortin II (UCNII) against a panel of Gram-positive and Gram-negative bacteria and tropical parasites of the genus Leishmania. Importantly, this cytotoxicity was selective for pathogens, because UCNII did not affect mammalian cell viability. Structurally, UCNII has a cationic and amphipathic design that resembles antimicrobial peptides. Using mutants and UCNII fragments, we determined the structural requirements for the interaction between the peptide and the surface of pathogen. Following its binding to pathogen, UCNII caused cell death through different membrane-disrupting mechanisms that involve aggregation and membrane depolarization in bacteria and pore formation in Leishmania. Noteworthily, UCNII killed the infective form of Leishmania major even inside the infected macrophages. Consequently, UCNII prevented mortality caused by polymicrobial sepsis and ameliorated pathological signs of cutaneous leishmaniasis. Besides its presence in body physical and mucosal barriers, we found that innate immune cells produce UCNII in response to infections. Therefore, UCNII could be considered as an ancient highly-conserved host peptide involved in the natural antimicrobial defense and emerge as an attractive alternative to current treatments for microbial disorders with associated drug resistances.