RESUMEN
CA2 pyramidal neurons (PNs) are associated with social behaviors. The mechanisms, however, remain to be fully investigated. Here, we report that Efr3b, a protein essential for phospholipid metabolism at the plasma membrane, is widely expressed in the brain, especially in the hippocampal CA2/CA3 areas. To assess the functional significance of Efr3b in the brain, we generated Efr3bf/f mice and crossed them with Nestin-cre mice to delete Efr3b specifically in the brain. We find that Efr3b deficiency in the brain leads to deficits of social novelty recognition and hypoexcitability of CA2 PNs. We then knocked down the expression of Efr3b specifically in CA2 PNs of C57BL/6J mice, and our results showed that reducing Efr3b in CA2 PNs also resulted in deficits of social novelty recognition and hypoexcitability of CA2 PNs. More interestingly, restoring the expression of Efr3b in CA2 PNs enhances their excitability and improves social novelty recognition in Efr3b-deficient mice. Furthermore, direct activation of CA2 PNs with chemogenetics improves social behaviors in Efr3b-deficient mice. Together, our data suggest that Efr3b is essential for social novelty by modulating the excitability of CA2 PNs.
Asunto(s)
Encéfalo , Reconocimiento en Psicología , Animales , Ratones , Ratones Endogámicos C57BL , Membrana Celular , Células PiramidalesRESUMEN
Adult neurogenesis is impaired in the hippocampus of patients with Alzheimer disease (AD) as well as AD models. However, it is far from clear how modulating adult neurogenesis affects AD neuropathology. We confirm that adult hippocampal neurogenesis is impaired in two AD models. Surprisingly, however, cognitive functions are improved in AD models after ablating adult neural stem cells (aNSCs). Ablation of aNSCs does not affect the levels of amyloid ß but restores the normal synaptic transmission in the dentate gyrus (DG) granule cells of AD models. Furthermore, calbindin depletion in the DG of AD mice is ameliorated after aNSC ablation, and knocking down calbindin abolishes the effects of aNSC ablation on synaptic and cognitive functions of AD mice. Together, our data suggest that cognitive functions of AD mice are improved after aNSC ablation, which is associated with the restoration of synaptic transmission in the DG granule cells with calbindin as an important mediator.
Asunto(s)
Enfermedad de Alzheimer/patología , Cognición/fisiología , Células-Madre Neurales/metabolismo , Transmisión Sináptica/fisiología , Enfermedad de Alzheimer/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animales , Calbindinas/deficiencia , Calbindinas/genética , Giro Dentado/citología , Giro Dentado/metabolismo , Modelos Animales de Enfermedad , Ganciclovir/farmacología , Humanos , Aprendizaje por Laberinto , Ratones Transgénicos , Células-Madre Neurales/citología , Células-Madre Neurales/efectos de los fármacos , Presenilina-1/genética , Presenilina-1/metabolismoRESUMEN
The fungicide imazalil (IMZ) is used extensively to protect vegetable fields, fruit plantations and post-harvest crops from rot. Likely due to its wide-spread use, IMZ is frequently detected in vegetable, fruit, soil and even surface water samples. Even though several previous studies have reported on the neurotoxicity of IMZ, its effects on the neurobehavior of zebrafish have received little attention to date. In this study, we show that the heartbeat and hatchability of zebrafish were significantly influenced by IMZ concentrations of 300 µg L(-1) or higher. Moreover, in zebrafish larvae, locomotor behaviors such as average swimming speed and swimming distance were significantly decreased after exposure to 300 µg L(-1) IMZ for 96 h, and acetylcholinesterase (AChE) expression and activity were consistently inhibited in IMZ-treated fish. Our results further suggest that IMZ could act as a neuroendocrine disruptor by decreasing the expression of neurotoxicity-related genes such as Glial fibrillary acidic protein (Gfap), Myelin basic protein (Mbp) and Sonic hedgehog a (Shha) during early developmental stages of zebrafish. In conclusion, we show that exposure to IMZ has the potential to induce developmental toxicity and locomotor behavior abnormalities during zebrafish development.
Asunto(s)
Inhibidores de la Colinesterasa/toxicidad , Fungicidas Industriales/toxicidad , Imidazoles/toxicidad , Larva/efectos de los fármacos , Contracción Miocárdica/efectos de los fármacos , Pez Cebra/embriología , Acetilcolinesterasa/metabolismo , Animales , Proteína Ácida Fibrilar de la Glía/biosíntesis , Proteínas Hedgehog/biosíntesis , Proteína Básica de Mielina/biosíntesis , Natación , Pez Cebra/metabolismo , Proteínas de Pez Cebra/biosíntesisRESUMEN
Atrazine (ATZ) and its main chlorometabolites, i.e., diaminochlorotriazine (DACT), deisopropylatrazine (DIP), and deethylatrazine (DE), have been widely detected in aquatic systems near agricultural fields. However, their possible effects on aquatic animals are still not fully understood. In this study, it was observed that several developmental endpoints such as the heart beat, hatchability, and morphological abnormalities were influenced by ATZ and its metabolites in different developmental stages. In addition, after 5 days of exposure to 30, 100, 300 µg L(-1) ATZ and its main chlorometabolites, the swimming behaviors of larval zebrafish were significantly disturbed, and the acetylcholinesterase (AChE) activities were consistently inhibited. Our results also demonstrate that ATZ and its main chlorometabolites are neuroendocrine disruptors that impact the expression of neurotoxicity-related genes such as Ache, Gap43, Gfap, Syn2a, Shha, Mbp, Elavl3, Nestin and Ngn1 in early developmental stages of zebrafish. According to our results, it is possible that not only ATZ but also its metabolites (DACT, DIP and DE) have the same or even more toxic effects on different endpoints of the early developmental stages of zebrafish.
