RESUMO
Neuronal calcium sensor-1 or Frequenin is a calcium sensor widely expressed in the nervous system, with roles in neurotransmission, neurite outgrowth, synaptic plasticity, learning, and motivated behaviours. Neuronal calcium sensor-1 has been implicated in neuropsychiatric disorders including autism spectrum disorder, schizophrenia, and bipolar disorder. However, the role of neuronal calcium sensor-1 in behavioural phenotypes and brain changes relevant to autism spectrum disorder have not been evaluated. We show that neuronal calcium sensor-1 deletion in the mouse leads to a mild deficit in social approach and impaired displaced object recognition without affecting social interactions, behavioural flexibility, spatial reference memory, anxiety-like behaviour, or sensorimotor gating. Morphologically, neuronal calcium sensor-1 deletion leads to increased dendritic arbour complexity in the frontal cortex. At the level of hippocampal synaptic plasticity, neuronal calcium sensor-1 deletion leads to a reduction in long-term potentiation in the dentate gyrus, but not area Cornu Ammonis 1. Metabotropic glutamate receptor-induced long-term depression was unaffected in both dentate and Cornu Ammonis 1. These studies identify roles for neuronal calcium sensor-1 in specific subregions of the brain including a phenotype relevant to neuropsychiatric disorders.
Assuntos
Comportamento de Escolha/fisiologia , Cognição/fisiologia , Potenciação de Longa Duração/genética , Proteínas Sensoras de Cálcio Neuronal/genética , Plasticidade Neuronal/genética , Neuropeptídeos/genética , Reconhecimento Psicológico/fisiologia , Animais , Ansiedade/genética , Região CA1 Hipocampal/fisiologia , Giro Denteado/fisiopatologia , Lobo Frontal/patologia , Camundongos , Camundongos Knockout , Receptores de Glutamato Metabotrópico , Filtro Sensorial/genética , Comportamento Social , Interação Social , Memória Espacial/fisiologiaRESUMO
Schizophrenia is thought to result from interactions between susceptible genotypes and environmental risk factors. DISC1 is an important gene for schizophrenia and mood disorders based on both human and animal studies. In the present study we sought to investigate interactions between two distinct point mutations in the mouse Disc1 gene (L100P and Q31L) and maternal immune activation (MIA) during pregnancy with polyinosinic:polycytidylic acid (polyI:C). PolyI:C given at 5 mg/kg impaired cognitive and social behavior in both wild-type (WT) and Disc1-Q31L(+/-) offspring, and reduced prepulse inhibition at 16 but not 8 weeks of age. Disc1-L100P(+/-) mutants were more sensitive to MIA than WT or Disc1-Q31L(+/-) mice. Interleukin-6 (IL-6) is a critical cytokine for mediating the behavioral and transcriptional effects of polyI:C. We found a more pronounced increase of IL-6 in response to polyI:C in fetal brain in Disc1-L100P(+/-) mice compared with WT or Disc1-Q31L(+/-) mice. Coadministration of an anti-IL-6 antibody with polyI:C reversed schizophrenia-related behavioral phenotypes in Disc1-L100P(+/-) mice. In summary, we found specific interactions between discrete genetic (Disc1-L100P(+/-)) and environmental factors (MIA) that exacerbate schizophrenia-related phenotypes. IL-6 may be important in the pathophysiology of this interaction.
Assuntos
Proteínas do Tecido Nervoso/genética , Mutação Puntual/genética , Efeitos Tardios da Exposição Pré-Natal/imunologia , Efeitos Tardios da Exposição Pré-Natal/fisiopatologia , Esquizofrenia/genética , Esquizofrenia/imunologia , Estimulação Acústica , Análise de Variância , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Aprendizagem em Labirinto/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Poli I-C/efeitos adversos , Gravidez , Reconhecimento Psicológico/fisiologia , Reflexo de Sobressalto/efeitos dos fármacos , Reflexo de Sobressalto/genética , Esquizofrenia/metabolismo , Esquizofrenia/fisiopatologia , Comportamento SocialRESUMO
The reticulon-4 receptor, encoded by RTN4R, limits axonal sprouting and neural plasticity by inhibiting the outgrowth of neurites. Human association studies have implicated mutations in RTN4R in the development of schizophrenia, including the identification of several rare nonconservative missense mutations of RTN4R in schizophrenia patients. To investigate the effects of missense mutation of the reticulon-4 receptor on phenotypes relevant to schizophrenia, we behaviourally characterized a novel Rtn4r mutant mouse line with an amino acid substitution (R189H) in the Nogo-66 binding site. Behavioural assays included prepulse inhibition of acoustic startle, locomotor activity, social interaction and spatial cognition. When compared with wildtype littermates, Rtn4r mutant mice exhibited greater social preference, which may reflect a social-anxyolitic effect, and a mild impairment in spatial cognition. Given the mild effect of the R189H mutation of Rtn4r on behavioural phenotypes relevant to schizophrenia, our results do not support missense mutation of RTN4R as a strong risk factor in the pathogenesis of schizophrenia.