RESUMO
Neural circuits that control aversion are essential for motivational regulation and survival in animals. The nucleus accumbens (NAc) plays an important role in predicting aversive events and translating motivations into actions. However, the NAc circuits that mediate aversive behaviors remain elusive. Here, we report that tachykinin precursor 1 (Tac1) neurons in the NAc medial shell regulate avoidance responses to aversive stimuli. We show that NAcTac1 neurons project to the lateral hypothalamic area (LH) and that the NAcTac1âLH pathway contributes to avoidance responses. Moreover, the medial prefrontal cortex (mPFC) sends excitatory inputs to the NAc, and this circuit is involved in the regulation of avoidance responses to aversive stimuli. Overall, our study reveals a discrete NAc Tac1 circuit that senses aversive stimuli and drives avoidance behaviors.
Assuntos
Neurônios , Núcleo Accumbens , Animais , Aprendizagem da Esquiva , Região Hipotalâmica Lateral , Motivação , Vias Neurais/fisiologia , Núcleo Accumbens/fisiologiaRESUMO
Chronic stress has been observed to increase the risk of developing depression and induce neuronal alterations of synaptic plasticity, yet the underlying molecular mechanisms remain unclear. Here, we found that the ubiquitously expressed RNA-binding protein HuR was up-regulated in the medial prefrontal cortex (mPFC) of mice following chronic stress. In adult mice, AAV-Cre-mediated knockout of HuR in the mPFC prevented anxiety-like and depression-like behaviors induced by chronic stress. HuR was also required for the stress-induced dendritic spine loss and synaptic transmission deficits. Moreover, HuRflox/flox;Nex-Cre mice, which induce HuR loss of function from embryonic development, exhibited enhanced synaptic functions. Notably, we ascertained RhoA signaling to be regulated by HuR and involved in the modulation of structural synaptic plasticity in response to chronic stress. Our results demonstrate HuR is a critical modulator for the regulation of stress-induced synaptic plasticity alterations and depression, providing a potential therapeutic target for the treatment of depressive disorders.
Assuntos
Depressão/metabolismo , Proteína Semelhante a ELAV 1/metabolismo , Plasticidade Neuronal/fisiologia , Córtex Pré-Frontal/metabolismo , Animais , Depressão/etiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Restrição Física , Estresse Psicológico/complicaçõesRESUMO
Single-chain variable fragment (scFv) antibodies are the smallest immunoglobulins with high antigen-binding affinity. We have previously reported that fibroblast growth factor 1 played pivotal roles in cancer development and generated a mouse scFv (mscFv1C9) could effectively prohibit cancer cell proliferation in vitro and in vivo. Here, we further humanized this scFv (hscFv1C9) using a structure-guided complementarity determining region grafting strategy. The purified hscFv1C9 maintained similar antigen-binding affinity and specificity as mscFv1C9, and it was capable of inhibiting growth of different tumours in vitro and in vivo. These data strongly suggested that hscFv1C9 has antitumour potentials.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Fator 1 de Crescimento de Fibroblastos/antagonistas & inibidores , Glioma/tratamento farmacológico , Anticorpos de Cadeia Única/farmacologia , Sequência de Aminoácidos/genética , Animais , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Monoclonais Humanizados/farmacologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Feminino , Fator 1 de Crescimento de Fibroblastos/química , Fator 1 de Crescimento de Fibroblastos/genética , Fator 1 de Crescimento de Fibroblastos/imunologia , Glioma/genética , Glioma/patologia , Xenoenxertos , Humanos , Camundongos , Anticorpos de Cadeia Única/imunologiaRESUMO
Major depressive disorder (MDD) presents with two primary symptoms: depressed mood and anhedonia, which suggests that distinct neuronal circuits may regulate MDD. However, the underlying circuits of these individual symptoms linked to depression remain elusive. Herein, we identify a discrete circuit of tachykinin precursor 1 (Tac1)-expressing neurons in the nucleus accumbens (NAc) lateral shell, which project to ventral pallidum and contribute to stress-induced anhedonia-like behavior. Selective inhibition and activation of Tac1NAc neurons bidirectionally modulate stress susceptibility, revealing that Tac1 neurons in the NAc are critical for regulating anhedonia-like behaviors. We find that a subpopulation of VP neurons receives inhibitory inputs from Tac1NAc neurons and exhibits decreased excitability in susceptible mice. Furthermore, the inhibition of the neurokinin 1 receptor promotes susceptibility to social stress. Overall, our study reveals a discrete circuit regulating anhedonia-like behavior in mice.
Assuntos
Anedonia/fisiologia , Comportamento Animal/fisiologia , Neurônios/metabolismo , Núcleo Accumbens/metabolismo , Precursores de Proteínas/metabolismo , Estresse Psicológico/fisiopatologia , Taquicininas/metabolismo , Animais , Suscetibilidade a Doenças , Técnicas de Silenciamento de Genes , Masculino , Camundongos Endogâmicos C57BL , Receptores da Neurocinina-1/metabolismo , Comportamento SocialRESUMO
Axonal development is essential to the establishment of neuronal morphology and circuitry, although the mechanisms underlying axonal outgrowth during the early developmental stages remain unclear. Here, we showed that the conserved disco-interacting protein B (DIP2B) which consists of a DMAP1 domain and a crotonobetaine/carnitine CoA ligase (Caic) domain, is highly expressed in the excitatory neurons of the hippocampus. DIP2B knockout led to excessive axonal outgrowth but not polarity at an early developmental stage. Furthermore, the loss of DIP2B inhibited synaptic transmission for both spontaneous and rapid release in cultured hippocampal neurons. Interestingly, DIP2B function during axonal outgrowth requires tubulin acetylation. These findings reveal a new conserved regulator of neuronal morphology and provide a novel intervention mechanism for neurocognitive disorders.
RESUMO
Gliomas, a common type of brain tumor, are characterized by aggressive infiltration, making it difficultly to cure by surgery. Netrin-1, an extracellular guidance cue critical for neuronal axon path-finding, has been reported to play an important role in cell invasion and migration in several types of cancers. However, the role of netrin-1 in glioma remains largely unknown. Here, we provide evidence suggested that Netrin-1 has a critical role in glioma growth. We found that netrin-1 was significantly increased in glioma samples and positively correlated with cell proliferation, tumor grade and malignancy. Netrin-1 knockdown reduced cell proliferation and attenuated tumor growth in a xenograft mouse model. Further studies found that netrin-1 induced NF-κB p65ser536 phosphorylation and c-Myc expression in vitro and in vivo. Interestingly, activation of NF-κB by netrin-1 was dependent on UNC5A receptor, because suppression of UNC5A significantly inhibited NF-κB p65ser536 phosphorylation, c-Myc up-regulation and reduced cell proliferation. Taken together, these results suggested netrin-1 promotes glioma cell proliferation by activating NF-κB signaling via UNC5A, netrin-1 may be a potential therapeutic target for the treatment of glioma.