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1.
Cell ; 160(3): 477-88, 2015 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-25619689

RESUMO

MYC is a highly pleiotropic transcription factor whose deregulation promotes cancer. In contrast, we find that Myc haploinsufficient (Myc(+/-)) mice exhibit increased lifespan. They show resistance to several age-associated pathologies, including osteoporosis, cardiac fibrosis, and immunosenescence. They also appear to be more active, with a higher metabolic rate and healthier lipid metabolism. Transcriptomic analysis reveals a gene expression signature enriched for metabolic and immune processes. The ancestral role of MYC as a regulator of ribosome biogenesis is reflected in reduced protein translation, which is inversely correlated with longevity. We also observe changes in nutrient and energy sensing pathways, including reduced serum IGF-1, increased AMPK activity, and decreased AKT, TOR, and S6K activities. In contrast to observations in other longevity models, Myc(+/-) mice do not show improvements in stress management pathways. Our findings indicate that MYC activity has a significant impact on longevity and multiple aspects of mammalian healthspan.


Assuntos
Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Envelhecimento , Animais , Tamanho Corporal , Feminino , Longevidade , Linfoma/genética , Masculino , Redes e Vias Metabólicas , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Transcriptoma
2.
Horm Behav ; 158: 105464, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38070354

RESUMO

Experiencing early life adversity (ELA) alters stress physiology and increases the risk for developing psychiatric disorders. The social environment can influence dynamics of stress responding and buffer and/or transfer stress across individuals. Yet, the impact of ELA on sensitivity to the stress of others and social behavior following stress is unknown. Here, to test the impact of ELA on social and physiological responses to stress, circulating blood corticosterone (CORT) and social behaviors were assessed in adult male and female mice reared under limited bedding and nesting (LBN) or control conditions. To induce stress, one cagemate of a pair-housed cage underwent a footshock paradigm and was then returned to their unshocked partner. CORT was measured in both groups of mice 20 or 90 min after stress exposure, and social behaviors were recorded and analyzed. ELA rearing influenced the CORT response to stress in a sex-specific manner. In males, both control and ELA-reared mice exhibited similar stress transfer to unshocked cagemates and similar CORT dynamics. In contrast, ELA females showed a heightened stress transfer to unshocked cagemates, and sustained elevation of CORT relative to controls, indicating enhanced stress contagion and a failure to terminate the stress response. Behaviorally, ELA females displayed decreased allogrooming and increased investigative behaviors, while ELA males showed reduced huddling. Together, these findings demonstrate that ELA influenced HPA axis dynamics, social stress contagion and social behavior. Further research is needed to unravel the underlying mechanisms and long-term consequences of ELA on stress systems and their impact on behavioral outcomes.


Assuntos
Experiências Adversas da Infância , Corticosterona , Humanos , Adulto , Camundongos , Masculino , Animais , Feminino , Sistema Hipotálamo-Hipofisário/fisiologia , Sistema Hipófise-Suprarrenal/fisiologia , Estresse Psicológico/psicologia
3.
Stress ; 26(1): 2244598, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37624104

RESUMO

Early life adversity (ELA) heightens the risk for anxiety disorders (which are characterized by heightened fear and avoidance behaviors), with females being twice as likely as males to develop pathology. Pavlovian fear conditioning tasks have been used to study possible mechanisms supporting endophenotypes of pathology. Identification of sex and ELA selective effects on the nature of behavioral responding in these paradigms may provide a unique window into coping strategies in response to learned fear to guide more mechanistic studies. The goals of this study were two-fold; First, to test if male and female mice employed different coping strategies in response to threat learning using different conditioning parameters (low, medium, and high intensity foot shocks). Second, to test if ELA in the form of limited bedding and nesting (LBN) altered the behavioral response of mice to conditioning. Mice received 6 tone/foot-shock pairings at one of three different foot-shock intensities (0.35 mA; 0.57 mA; 0.7 mA). Freezing, darting, and foot-shock reactivity were measured across trials. During conditioning, control-reared female mice exhibited significantly higher rates of darting behavior compared to control males at nearly all shock intensities tested. LBN rearing decreased the proportion of darting females to levels observed in males. Thus, ELA in the form of LBN significantly diminished the recruitment of active versus passive coping strategies in female mice but did not generally change male responding. Additional work will be required to understand the neural basis of these behavioral effects. Findings extending from this work have the potential to shed light on how ELA impacts trajectories of regional brain development with implications for sex-selective risk for behavioral endophenotypes associated with pathology and possibly symptom presentation.


Assuntos
Caracteres Sexuais , Estresse Psicológico , Animais , Feminino , Masculino , Camundongos , Adaptação Psicológica , Aprendizagem
4.
Chem Senses ; 462021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-34618883

RESUMO

Links between olfactory sensory function and effect have been well established. A robust literature exists in both humans and animals showing that disrupting olfaction sensory function can elicit disordered mood state, including serve as a model of depression. Despite this, considerably less is known regarding the directionality and neural basis of this relationship, e.g. whether disruptions in sensory function precede and contribute to altered mood or if altered mood state precipitates changes in olfactory perception. Further, the neural basis of altered olfactory function in depression remains unclear. In conjunction with clinical studies, animal models represent a valuable tool to understand the relationship between altered mood and olfactory sensory function. Here, we review the relevant literature assessing olfactory performance in depression in humans and in rodent models of depressive-like behavioral states. Rodents allow for detailed characterization of alterations in olfactory perception, manipulation of experiential events that elicit depressive-like phenotypes, and allow for interrogation of potential predictive markers of disease and the cellular basis of olfactory impairments associated with depressive-like phenotypes. We synthesize these findings to identify paths forward to investigate and understand the complex interplay between depression and olfactory sensory function.


Assuntos
Transtornos do Olfato , Percepção Olfatória , Animais , Depressão , Olfato
5.
Front Neuroendocrinol ; 54: 100768, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31175880

RESUMO

Various forms of early life adversity (ELA) have been linked with increased risk for negative health outcomes, including neuropsychiatric disorders. Understanding how the complex interplay between types, timing, duration, and severity of ELA, together with individual differences in genetic, socio-cultural, and physiological differences can mediate risk and resilience has proven difficult in population based studies. Use of animal models provides a powerful toolset to isolate key variables underlying risk for altered neural and behavioral maturational trajectories. However, a lack of clarity regarding the unique features of differing forms of adversity, lab differences in the implementation and reporting of methods, and the ability compare across labs and types of ELA has led to some confusion. Here, we highlight the diversity of approaches available, current challenges, and a possible ways forward to increase clarity and drive more meaningful and fruitful implementation and comparison of these approaches.


Assuntos
Experiências Adversas da Infância , Desenvolvimento Infantil , Modelos Animais de Doenças , Resiliência Psicológica , Estresse Psicológico , Animais , Criança , Humanos
6.
Horm Behav ; 124: 104763, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32407728

RESUMO

Early life adversity (ELA) increases risk for negative health outcomes, with sex disparities in prevalence and form of ELA experienced and risk for neuropsychiatric pathology. ELA comes in many forms (e.g. parental neglect/loss, limited access to resources) but whether disparate forms of ELA have common effects on outcomes, and if males and females are equally affected, remains unknown. Epidemiological studies often fail to accurately account for differences in type, timing, and duration of adversity experienced. Rodent models allow precise control of many of these variables. However, differences in the form of ELA, species, strain, housing, and testing paradigms used may contribute to differences in outcomes leading to questions of whether differences are the result of the form of ELA or these other variables. Here, we directly compared two mouse models of ELA, maternal separation (MS) and limited bedding (LB) in males and females on development of the body, motor and visual milestones, stress physiology, and anxiety-like behavior. LB affected timing of early milestones, somatic growth, and stress physiology in both sexes, yet only females showed later anxiety-like behaviors. MS rearing affected males and females similarly in early milestone development, yet only males showed changes in stress physiology and anxiety-like outcomes. These studies provide a platform to directly compare MS and LB models within one lab. The current work advances our understanding of the unique features of ELA that shape early neurodevelopmental events and risk for later pathology, increasing the translational relevance of these ELA models.


Assuntos
Crescimento e Desenvolvimento/fisiologia , Privação Materna , Estresse Fisiológico/fisiologia , Estresse Psicológico/fisiopatologia , Animais , Animais Recém-Nascidos , Ansiedade/fisiopatologia , Modelos Animais de Doenças , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Caracteres Sexuais , Estresse Psicológico/psicologia
7.
J Neurosci ; 38(44): 9433-9445, 2018 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-30381435

RESUMO

The ability to anticipate and respond appropriately to the challenges and opportunities present in our environments is critical for adaptive behavior. Recent methodological innovations have led to substantial advances in our understanding of the neurocircuitry supporting such motivated behavior in adulthood. However, the neural circuits and cognitive processes that enable threat- and reward-motivated behavior undergo substantive changes over the course of development, and these changes are less well understood. In this article, we highlight recent research in human and animal models demonstrating how developmental changes in prefrontal-subcortical neural circuits give rise to corresponding changes in the processing of threats and rewards from infancy to adulthood. We discuss how these developmental trajectories are altered by experiential factors, such as early-life stress, and highlight the relevance of this research for understanding the developmental onset and treatment of psychiatric disorders characterized by dysregulation of motivated behavior.


Assuntos
Adaptação Psicológica/fisiologia , Desenvolvimento Infantil/fisiologia , Cognição/fisiologia , Motivação/fisiologia , Rede Nervosa/crescimento & desenvolvimento , Córtex Pré-Frontal/crescimento & desenvolvimento , Adolescente , Criança , Humanos , Estresse Psicológico/fisiopatologia , Estresse Psicológico/psicologia
8.
Proc Natl Acad Sci U S A ; 112(51): 15737-42, 2015 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-26630005

RESUMO

Neurotrophins and glucocorticoids are robust synaptic modifiers, and deregulation of their activities is a risk factor for developing stress-related disorders. Low levels of brain-derived neurotrophic factor (BDNF) increase the desensitization of glucocorticoid receptors (GR) and vulnerability to stress, whereas higher levels of BDNF facilitate GR-mediated signaling and the response to antidepressants. However, the molecular mechanism underlying neurotrophic-priming of GR function is poorly understood. Here we provide evidence that activation of a TrkB-MAPK pathway, when paired with the deactivation of a GR-protein phosphatase 5 pathway, resulted in sustained GR phosphorylation at BDNF-sensitive sites that is essential for the transcription of neuronal plasticity genes. Genetic strategies that disrupted GR phosphorylation or TrkB signaling in vivo impaired the neuroplasticity to chronic stress and the effects of the antidepressant fluoxetine. Our findings reveal that the coordinated actions of BDNF and glucocorticoids promote neuronal plasticity and that disruption in either pathway could set the stage for the development of stress-induced psychiatric diseases.


Assuntos
Antidepressivos/farmacologia , Plasticidade Neuronal/fisiologia , Receptores de Glucocorticoides/fisiologia , Transdução de Sinais/fisiologia , Estresse Psicológico/fisiopatologia , Animais , Fator Neurotrófico Derivado do Encéfalo/fisiologia , Feminino , Fluoxetina/farmacologia , Sistema de Sinalização das MAP Quinases , Glicoproteínas de Membrana/fisiologia , Camundongos , Plasticidade Neuronal/efeitos dos fármacos , Fosforilação , Proteínas Tirosina Quinases/fisiologia , Ratos , Ratos Sprague-Dawley , Receptor trkB
9.
J Neurosci ; 36(4): 1211-22, 2016 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-26818509

RESUMO

Considerable evidence suggests that multiple learning systems can drive behavior. Choice can proceed reflexively from previous actions and their associated outcomes, as captured by "model-free" learning algorithms, or flexibly from prospective consideration of outcomes that might occur, as captured by "model-based" learning algorithms. However, differential contributions of dopamine to these systems are poorly understood. Dopamine is widely thought to support model-free learning by modulating plasticity in striatum. Model-based learning may also be affected by these striatal effects, or by other dopaminergic effects elsewhere, notably on prefrontal working memory function. Indeed, prominent demonstrations linking striatal dopamine to putatively model-free learning did not rule out model-based effects, whereas other studies have reported dopaminergic modulation of verifiably model-based learning, but without distinguishing a prefrontal versus striatal locus. To clarify the relationships between dopamine, neural systems, and learning strategies, we combine a genetic association approach in humans with two well-studied reinforcement learning tasks: one isolating model-based from model-free behavior and the other sensitive to key aspects of striatal plasticity. Prefrontal function was indexed by a polymorphism in the COMT gene, differences of which reflect dopamine levels in the prefrontal cortex. This polymorphism has been associated with differences in prefrontal activity and working memory. Striatal function was indexed by a gene coding for DARPP-32, which is densely expressed in the striatum where it is necessary for synaptic plasticity. We found evidence for our hypothesis that variations in prefrontal dopamine relate to model-based learning, whereas variations in striatal dopamine function relate to model-free learning. SIGNIFICANCE STATEMENT: Decisions can stem reflexively from their previously associated outcomes or flexibly from deliberative consideration of potential choice outcomes. Research implicates a dopamine-dependent striatal learning mechanism in the former type of choice. Although recent work has indicated that dopamine is also involved in flexible, goal-directed decision-making, it remains unclear whether it also contributes via striatum or via the dopamine-dependent working memory function of prefrontal cortex. We examined genetic indices of dopamine function in these regions and their relation to the two choice strategies. We found that striatal dopamine function related most clearly to the reflexive strategy, as previously shown, and that prefrontal dopamine related most clearly to the flexible strategy. These findings suggest that dissociable brain regions support dissociable choice strategies.


Assuntos
Encéfalo/fisiologia , Catecol O-Metiltransferase/genética , Fosfoproteína 32 Regulada por cAMP e Dopamina/genética , Aprendizagem/fisiologia , Modelos Psicológicos , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Adulto , Mapeamento Encefálico , Tomada de Decisões/fisiologia , Dopamina/metabolismo , Feminino , Humanos , Modelos Logísticos , Masculino , Reforço Psicológico , Transferência de Experiência , Adulto Jovem
10.
Neurobiol Learn Mem ; 143: 36-48, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28458034

RESUMO

The capacity to learn to associate cues with negative outcomes is a highly adaptive process that appears to be conserved across species. However, when the cue is no longer a valid predictor of danger, but the emotional response persists, this can result in maladaptive behaviors, and in humans contribute to debilitating emotional disorders. Over the past several decades, work in neuroscience, psychiatry, psychology, and biology have uncovered key processes underlying, and structures governing, emotional responding and learning, as well as identified disruptions in the structural and functional integrity of these brain regions in models of pathology. In this review, we highlight some of this elegant body of work as well as incorporate emerging findings from the field of developmental neurobiology to emphasize how development contributes to changes in the ability to learn and express emotional responses, and how early experiences, such as stress, shape the development and functioning of these circuits.


Assuntos
Emoções , Medo , Aprendizagem , Acontecimentos que Mudam a Vida , Estresse Psicológico , Animais , Encéfalo/crescimento & desenvolvimento , Encéfalo/fisiologia , Condicionamento Clássico , Extinção Psicológica , Humanos
11.
Stress ; 20(5): 421-448, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28617197

RESUMO

The immediate and long-term effects of exposure to early life stress (ELS) have been documented in humans and animal models. Even relatively brief periods of stress during the first 10 days of life in rodents can impact later behavioral regulation and the vulnerability to develop adult pathologies, in particular an impairment of cognitive functions and neurogenesis, but also modified social, emotional, and conditioned fear responses. The development of preclinical models of ELS exposure allows the examination of mechanisms and testing of therapeutic approaches that are not possible in humans. Here, we describe limited bedding and nesting (LBN) procedures, with models that produce altered maternal behavior ranging from fragmentation of care to maltreatment of infants. The purpose of this paper is to discuss important issues related to the implementation of this chronic ELS procedure and to describe some of the most prominent endpoints and consequences, focusing on areas of convergence between laboratories. Effects on the hypothalamic-pituitary adrenal (HPA) axis, gut axis and metabolism are presented in addition to changes in cognitive and emotional functions. Interestingly, recent data have suggested a strong sex difference in some of the reported consequences of the LBN paradigm, with females being more resilient in general than males. As both the chronic and intermittent variants of the LBN procedure have profound consequences on the offspring with minimal external intervention from the investigator, this model is advantageous ecologically and has a large translational potential. In addition to the direct effect of ELS on neurodevelopmental outcomes, exposure to adverse early environments can also have intergenerational impacts on mental health and function in subsequent generation offspring. Thus, advancing our understanding of the effect of ELS on brain and behavioral development is of critical concern for the health and wellbeing of both the current population, and for generations to come.


Assuntos
Maus-Tratos Infantis , Cognição , Emoções , Comportamento Materno , Comportamento de Nidação , Estresse Psicológico/psicologia , Tecido Adiposo Branco/metabolismo , Animais , Animais Recém-Nascidos , Roupas de Cama, Mesa e Banho , Comportamento Animal , Epigênese Genética , Feminino , Humanos , Sistema Hipotálamo-Hipofisário/metabolismo , Recém-Nascido , Masculino , Modelos Animais , Neurogênese , Sistema Hipófise-Suprarrenal/metabolismo , Reprodutibilidade dos Testes , Resiliência Psicológica , Roedores , Fatores Sexuais , Estresse Psicológico/metabolismo
12.
Epilepsy Behav ; 70(Pt A): 110-117, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28412607

RESUMO

Valproate has been used for over 30years as a first-line treatment for epilepsy. In recent years, prenatal exposure to valproate has been associated with teratogenic effects, limiting its use in women that are pregnant or of childbearing age. However, despite its potential detrimental effects on development, valproate continues to be prescribed at high rates in pediatric populations in some countries. Animal models allow us to test hypotheses regarding the potential effects of postnatal valproate exposure on neurobehavioral development, as well as identify potential mechanisms mediating observed effects. Here, we tested the effect of early postnatal (P4-P11) valproate exposure (100mg/kg and 200mg/kg) on motor and affective development in two strains of mice, SVE129 and C57Bl/6N. We also assessed the effect of early valproate exposure on regional BDNF protein levels, a potential target of valproate, and mediator of neurodevelopmental outcomes. We found that early life valproate exposure led to significant motor impairments in both SVE129 and C57Bl/6N mice. Both lines of mice showed significant delays in weight gain, as well as impairments in the righting reflex (P7-8), wire hang (P17), open field (P12 and P21), and rotarod (P25 and P45) tasks. Interestingly, some of the early locomotor effects were strain- and dose-dependent. We observed no effects of valproate on early markers of anxiety-like behavior. Importantly, early life valproate exposure had significant effects on regional BDNF expression, leading to a near 50% decrease in BDNF levels in the cerebellum of both strains of mice, while not impacting hippocampal BDNF protein levels. These observations indicate that postnatal exposure to valproate may have significant, and region-specific effects, on neural and behavioral development, with specific consequences for cerebellar development and motor function.


Assuntos
Comportamento Animal/fisiologia , Fator Neurotrófico Derivado do Encéfalo/biossíntese , Cerebelo/metabolismo , Hipocampo/metabolismo , Atividade Motora/fisiologia , Ácido Valproico/toxicidade , Animais , Animais Recém-Nascidos , Anticonvulsivantes/administração & dosagem , Anticonvulsivantes/toxicidade , Ansiedade/induzido quimicamente , Ansiedade/metabolismo , Ansiedade/psicologia , Comportamento Animal/efeitos dos fármacos , Cerebelo/crescimento & desenvolvimento , Feminino , Expressão Gênica/genética , Hipocampo/efeitos dos fármacos , Hipocampo/crescimento & desenvolvimento , Masculino , Camundongos , Camundongos da Linhagem 129 , Camundongos Endogâmicos C57BL , Atividade Motora/efeitos dos fármacos , Gravidez , Reflexo de Endireitamento/efeitos dos fármacos , Reflexo de Endireitamento/fisiologia , Especificidade da Espécie , Ácido Valproico/administração & dosagem
13.
Chem Senses ; 40(5): 345-50, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25917509

RESUMO

Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability and is characterized by cognitive impairments and altered sensory function. It is caused by absence of fragile X mental retardation protein (FMRP), an RNA-binding protein essential for normal synaptic plasticity and function. Animal models have provided important insights into mechanisms through which loss of FMRP impacts cognitive and sensory development and function. While FMRP is highly enriched in the developing and adult olfactory bulb (OB), its role in olfactory sensory function remains poorly understood. Here, we used a mouse model of FXS, the fmr1 (-/y) mouse, to test whether loss of FMRP impacts olfactory discrimination, habituation, or sensitivity using a spontaneous olfactory cross-habituation task at a range of odorant concentrations. We demonstrated that fmr1 (-/y) mice have a significant decrease in olfactory sensitivity compared with wild type controls. When we controlled for differences in sensitivity, we found no effect of loss of FMRP on the ability to habituate to or spontaneously discriminate between odorants. These data indicate that loss of FMRP significantly alters olfactory sensitivity, but not other facets of basal olfactory function. These findings have important implications for future studies aimed at understanding the role of FMRP on sensory functioning.


Assuntos
Proteína do X Frágil da Deficiência Intelectual/metabolismo , Odorantes , Condutos Olfatórios/metabolismo , Percepção Olfatória/fisiologia , Animais , Modelos Animais de Doenças , Proteína do X Frágil da Deficiência Intelectual/genética , Síndrome do Cromossomo X Frágil/genética , Síndrome do Cromossomo X Frágil/metabolismo , Deleção de Genes , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout
14.
Proc Natl Acad Sci U S A ; 109(4): 1305-10, 2012 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-22232675

RESUMO

Regulation of the hypothalamic-pituitary-adrenal (HPA) axis is critical for adaptation to environmental changes. The principle regulator of the HPA axis is corticotrophin-releasing hormone (CRH), which is made in the parventricular nucleus and is an important target of negative feedback by glucocorticoids. However, the molecular mechanisms that regulate CRH are not fully understood. Disruption of normal HPA axis activity is a major risk factor of neuropsychiatric disorders in which decreased expression of the glucocorticoid receptor (GR) has been documented. To investigate the role of the GR in CRH neurons, we have targeted the deletion of the GR, specifically in the parventricular nucleus. Impairment of GR function in the parventricular nucleus resulted in an enhancement of CRH expression and an up-regulation of hypothalamic levels of BDNF and disinhibition of the HPA axis. BDNF is a stress and activity-dependent factor involved in many activities modulated by the HPA axis. Significantly, ectopic expression of BDNF in vivo increased CRH, whereas reduced expression of BDNF, or its receptor TrkB, decreased CRH expression and normal HPA functions. We find the differential regulation of CRH relies upon the cAMP response-element binding protein coactivator CRTC2, which serves as a switch for BDNF and glucocorticoids to direct the expression of CRH.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/metabolismo , Hormônio Liberador da Corticotropina/metabolismo , Glucocorticoides/metabolismo , Homeostase/fisiologia , Hipotálamo/fisiologia , Receptores de Glucocorticoides/metabolismo , Transativadores/metabolismo , Análise de Variância , Animais , Imunoprecipitação da Cromatina , Sistema Hipotálamo-Hipofisário/fisiologia , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia Confocal , Mutagênese Sítio-Dirigida , Neurônios/metabolismo , Sistema Hipófise-Suprarrenal/fisiologia , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição
15.
Dev Neurosci ; 36(3-4): 269-76, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24992985

RESUMO

Brain-derived neurotrophic factor (BDNF) is a growth factor that plays key roles in regulating higher-order emotional and cognitive processes including fear learning and memory. A common single-nucleotide polymorphism (SNP) has been identified in the human BDNF gene (BDNF Val66Met) that leads to decreased BDNF secretion and impairments in specific forms of fear learning in adult humans and genetically modified mice containing this SNP. As the emergence of anxiety and other fear-related disorders peaks during adolescence, we sought to better understand the impact of this BDNF SNP on fear learning during the transition through adolescence in BDNF Val66Met knock-in mice. Previously, we have shown that contextual fear expression is temporarily suppressed in wild-type mice during a distinct period in adolescence, but re-emerges at later, postadolescent ages. Until recently, it was unclear whether BDNF-TrkB signaling is involved in the modulation of hippocampal-dependent contextual fear learning and memory during this adolescent period. Here we show that in BDNF Val66Met mice, the presence of the Met allele does not alter contextual fear expression during adolescence, but when previously conditioned BDNF(Met/Met) mice are tested in adulthood, they fail to display the delayed expression of contextual fear compared to wild-type BDNF(Val/Val) controls, indicating that the Met allele may permanently alter hippocampal function, leading to persistent functioning that is indistinguishable from the adolescent state. Conversely, truncated TrkB receptor (TrkB.T1)-deficient (TrkB.T1(-/-)) mice, a genetic mouse model with increased BDNF-TrkB signaling through full-length TrkB receptors, exhibit an accelerated expression of contextual fear during adolescence compared to wild-type controls. Our results point to a critical function for BDNF-TrkB signaling in fear regulation in vivo, particularly during a potentially sensitive period in adolescence.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Fator Neurotrófico Derivado do Encéfalo/fisiologia , Medo/psicologia , Aprendizagem/fisiologia , Envelhecimento/psicologia , Animais , Gliceraldeído-3-Fosfato Desidrogenases/fisiologia , Hipocampo/fisiologia , Masculino , Camundongos , Camundongos Knockout , Polimorfismo de Nucleotídeo Único , Receptor trkB/genética
16.
Proc Natl Acad Sci U S A ; 108(3): 1182-7, 2011 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-21220344

RESUMO

Highly conserved neural circuitry between rodents and humans has allowed for in-depth characterization of behavioral and molecular processes associated with emotional learning and memory. Despite increased prevalence of affective disorders in adolescent humans, few studies have characterized how associative-emotional learning changes during the transition through adolescence or identified mechanisms underlying such changes. By examining fear conditioning in mice, as they transitioned into and out of adolescence, we found that a suppression of contextual fear occurs during adolescence. Although contextual fear memories were not expressed during early adolescence, they could be retrieved and expressed as the mice transitioned out of adolescence. This temporary suppression of contextual fear was associated with blunted synaptic activity in the basal amygdala and decreased PI3K and MAPK signaling in the hippocampus. These findings reveal a unique form of brain plasticity in fear learning during early adolescence and may prove informative for understanding endogenous mechanisms to suppress unwanted fear memories.


Assuntos
Tonsila do Cerebelo/fisiologia , Aprendizagem por Associação/fisiologia , Medo/psicologia , Hipocampo/fisiologia , Memória/fisiologia , Psicologia do Adolescente , Transdução de Sinais/fisiologia , Análise de Variância , Animais , Western Blotting , Condicionamento Psicológico/fisiologia , Eletrofisiologia , Medo/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Camundongos , Fosfatidilinositol 3-Quinases/metabolismo
17.
Brain Behav Immun Health ; 38: 100760, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38586284

RESUMO

Multisystem Inflammatory Syndrome in Children (MIS-C) is a secondary immune manifestation of COVID-19 involving multiple organ systems in the body, resulting in fever, skin rash, abdominal pain, nausea, shock, and cardiac dysfunction that often lead to hospitalization. Although many of these symptoms resolve following anti-inflammatory treatment, the long-term neurological and psychiatric sequelae of MIS-C are unknown. In this review, we will summarize two domains of the MIS-C disease course, 1) Neuroinflammation in the MIS-C brain and 2) Psychosocial disruptions resulting from stress and hospitalization. In both domains, we present existing clinical findings and hypothesize potential connections to psychiatric outcomes. This is the first review to conceptualize a holistic framework of psychiatric risk in MIS-C patients that includes neuroinflammatory and psychosocial risk factors. As cases of severe COVID-19 and MIS-C subside, it is important for clinicians to monitor outcomes in this vulnerable patient population.

18.
Nat Commun ; 15(1): 5522, 2024 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-38951506

RESUMO

Failure to appropriately predict and titrate reactivity to threat is a core feature of fear and anxiety-related disorders and is common following early life adversity (ELA). A population of neurons in the lateral central amygdala (CeAL) expressing corticotropin releasing factor (CRF) have been proposed to be key in processing threat of different intensities to mediate active fear expression. Here, we use in vivo fiber photometry to show that ELA results in sex-specific changes in the activity of CeAL CRF+ neurons, yielding divergent mechanisms underlying the augmented startle in ELA mice, a translationally relevant behavior indicative of heightened threat reactivity and hypervigilance. Further, chemogenic inhibition of CeAL CRF+ neurons selectively diminishes startle and produces a long-lasting suppression of threat reactivity. These findings identify a mechanism for sex-differences in susceptibility for anxiety following ELA and have broad implications for understanding the neural circuitry that encodes and gates the behavioral expression of fear.


Assuntos
Ansiedade , Núcleo Central da Amígdala , Hormônio Liberador da Corticotropina , Medo , Neurônios , Reflexo de Sobressalto , Animais , Hormônio Liberador da Corticotropina/metabolismo , Medo/fisiologia , Neurônios/metabolismo , Neurônios/fisiologia , Camundongos , Feminino , Masculino , Ansiedade/fisiopatologia , Núcleo Central da Amígdala/metabolismo , Reflexo de Sobressalto/fisiologia , Camundongos Endogâmicos C57BL , Comportamento Animal/fisiologia , Estresse Psicológico
19.
J Neurosci ; 32(7): 2410-21, 2012 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-22396415

RESUMO

The brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is a common human single nucleotide polymorphism (SNP) that affects the regulated release of BDNF, and has been implicated in affective disorders and cognitive dysfunction. A decreased activation of the infralimbic medial prefrontal cortex (IL-mPFC), a brain region critical for the regulation of affective behaviors, has been described in BDNF(Met) carriers. However, it is unclear whether and how the Val66Met polymorphism affects the IL-mPFC synapses. Here, we report that spike timing-dependent plasticity (STDP) was absent in the IL-mPFC pyramidal neurons from BDNF(Met/Met) mice, a mouse that recapitulates the specific phenotypic properties of the human BDNF Val66Met polymorphism. Also, we observed a decrease in NMDA and GABA receptor-mediated synaptic transmission in the pyramidal neurons of BDNF(Met/Met) mice. While BDNF enhanced non-NMDA receptor transmission and depressed GABA receptor transmission in the wild-type mice, both effects were absent in BDNF(Met/Met) mice after BDNF treatment. Indeed, exogenous BDNF reversed the deficits in STDP and NMDA receptor transmission in BDNF(Met/Met) neurons. BDNF-mediated selective reversal of the deficit in plasticity and NMDA receptor transmission, but its lack of effect on GABA and non-NMDA receptor transmission in BDNF(Met/Met) mice, suggests separate mechanisms of Val66Met polymorphism upon synaptic transmission. The effect of the Val66Met polymorphism on synaptic transmission and plasticity in the IL-mPFC represents a mechanism to account for this impact of SNP on affective disorders and cognitive dysfunction.


Assuntos
Fator Neurotrófico Derivado do Encéfalo/genética , Metionina/genética , Polimorfismo de Nucleotídeo Único/genética , Córtex Pré-Frontal/fisiologia , Transmissão Sináptica/fisiologia , Valina/genética , Animais , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Medo/fisiologia , Humanos , Masculino , Camundongos , Camundongos Transgênicos , Plasticidade Neuronal/fisiologia , Córtex Pré-Frontal/metabolismo , Células Piramidais/metabolismo , Células Piramidais/fisiologia
20.
Epilepsia ; 54 Suppl 4: 44-60, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23909853

RESUMO

Many symptoms of neurologic or psychiatric illness--such as cognitive impairment, depression, anxiety, attention deficits, and migraine--occur more frequently in people with epilepsy than in the general population. These diverse comorbidities present an underappreciated problem for people with epilepsy and their caregivers because they decrease quality of life, complicate treatment, and increase mortality. In fact, it has been suggested that comorbidities can have a greater effect on quality of life in people with epilepsy than the seizures themselves. There is increasing recognition of the frequency and impact of cognitive and behavioral comorbidities of epilepsy, highlighted in the 2012 Institute of Medicine report on epilepsy. Comorbidities have also been acknowledged, as a National Institutes of Health (NIH) Benchmark area for research in epilepsy. However, relatively little progress has been made in developing new therapies directed specifically at comorbidities. On the other hand, there have been many advances in understanding underlying mechanisms. These advances have made it possible to identify novel targets for therapy and prevention. As part of the International League Against Epilepsy/American Epilepsy Society workshop on preclinical therapy development for epilepsy, our working group considered the current state of understanding related to terminology, models, and strategies for therapy development for the comorbidities of epilepsy. Herein we summarize our findings and suggest ways to accelerate development of new therapies. We also consider important issues to improve research including those related to methodology, nonpharmacologic therapies, biomarkers, and infrastructure.


Assuntos
Transtornos Cognitivos/tratamento farmacológico , Descoberta de Drogas , Drogas em Investigação/uso terapêutico , Epilepsia/tratamento farmacológico , Transtornos Neurocognitivos/tratamento farmacológico , Animais , Transtornos de Ansiedade/induzido quimicamente , Transtornos de Ansiedade/tratamento farmacológico , Transtornos de Ansiedade/psicologia , Transtorno do Deficit de Atenção com Hiperatividade/induzido quimicamente , Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Transtorno do Deficit de Atenção com Hiperatividade/psicologia , Transtornos Cognitivos/induzido quimicamente , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/psicologia , Comorbidade , Transtorno Depressivo/induzido quimicamente , Transtorno Depressivo/tratamento farmacológico , Transtorno Depressivo/psicologia , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Drogas em Investigação/efeitos adversos , Epilepsia/diagnóstico , Epilepsia/psicologia , Humanos , Transtornos de Enxaqueca/induzido quimicamente , Transtornos de Enxaqueca/tratamento farmacológico , Transtornos de Enxaqueca/psicologia , Transtornos Neurocognitivos/induzido quimicamente , Transtornos Neurocognitivos/diagnóstico , Transtornos Neurocognitivos/psicologia , Qualidade de Vida/psicologia , Pesquisa Translacional Biomédica
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