2021-01-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/700607癲癇為一個高盛行率的大腦疾病，然而其致病機轉，仍尚未完全清楚。在部分癲癇的病人中，會出現RBFOX3基因的損壞，而RBFOX3在大腦內所扮演的生理角色，也尚未清楚。我們之前利用Rbfox3剔除小鼠，首次證明了RBFOX3的缺失，會造成癲癇的形成，此因果關係，指出了RBFOX3在癲癇形成的重要角色。此外，我們的研究，證明了RBFOX3對海馬體的神經迴路之形成、平衡及功能，扮演重要的角色。我們的研究，也證明了RBFOX3會調控神經細胞的增生及突觸的形成。雖然，我們過去的研究成果，幫助我們更進一步地了解RBFOX3在大腦的功能，但是我們對RBFOX3如何導致癲癇的詳細機轉，仍尚未清楚。我們將利用條件性Rbfox3剔除小鼠，並且聚焦在大腦海馬體內的齒狀回，來回答這一個重要的問題。大腦海馬體內的齒狀回，可防止海馬體過度興奮而導致癲癇發作。我們初步的結果指出，抑制性神經元而非興奮性神經元或齒狀迴顆粒細胞內的RBFOX3缺失，會導致嚴重性的自發性癲癇。我們將根據這個重要的線索，來從神經迴路、細胞及分子層次，深入地研究RBFOX3如何導致癲癇之詳細機轉。完成此計畫，我們將會提供第一個有關RBFOX3在大腦內不同細胞型態中，所扮演的生理角色之活體證據，並且提供RBFOX3造成癲癇的致病機轉。我們的研究成果，有可能提供治療癲癇的新模式。 Epilepsy is one of the most common neurological disorders affecting individuals of all ages and is characterized by recurrent, unprovoked seizures. Its prevalence rate is 7 out of 1,000 people. The exact causal mechanism for epilepsy is unclear. RBFOX3 is a neuron-specific alternative splicing regulator. Although the physiological role of RBFOX3 in the brain is not well understood, disruptions of RBFOX3 have been identified in persons with epilepsy and cognitive impairments. Through support from the MoST grant (104-2314-B-002-078-MY3, from 2015/8/1 to 2018/7/31), we provided the first evidence of a causal link between the disruption of Rbfox3 and epilepsy and cognitive impairments using Rbfox3 homozygous knockout mice. Moreover, we demonstrated that RBFOX3 is required for hippocampal circuit balance and function, in addition to adult hippocampal neurogenesis and synaptogenesis. Although we have made progress in understanding the functional roles of RBFOX3 in the brain, the mechanisms for how dysfunctional RBFOX3 contributes to epilepsy have yet to be elucidated. To address this critical question, we chose the hippocampal dentate gyrus as a target of our study. The hippocampal dentate gyrus (DG) serves as a filter for protecting against hyperexcitability and hippocampal synchronization leading to temporal lobe seizures. In addition, we have demonstrated that increased seizure susceptibility and severity occurs in Rbfox3 homozygous knockout mice treated with kainic acid. Treatment with kainic acid has been widely used as a model of temporal lobe epilepsy. Next, to enable genetic dissection of cell-typespecific contributions to circuit imbalance in epilepsy with dysfunctional RBFOX3, we generated conditional Rbfox3 knockout mice in which Cre was specifically expressed in excitatory neurons, GABAergic neurons, and hippocampal granule cells, respectively. Our preliminary results showed that Rbfox3 was robustly deleted in a cell-type-specific manner in the three types of conditional Rbfox3 knockout mice. Although all three types of conditional Rbfox3 knockout mice with celltype-specificity exhibited normal body weight regardless of gender, mice with GABAergic neuron-specific Rbfox3 deletion showed a decrease in survival rate, whose severity was proportional to the degree of Rbfox3 deletion. In contrast, mice with excitatory neuron- or granule cellspecific Rbfox3 deletion did not show a decrease in survival rate. We also found that Gad2-Cre::Rbfox3loxp/loxp mice experienced spontaneous seizures, which was determined to be the cause of death. Our preliminary results indicate that RBFOX3 in GABAergic neurons is responsible for mediating spontaneous seizures.癲癇RBFOX3NeuN抑制性神經元海馬體神經發育神經興奮性及抑制性平衡神經迴路神經突觸傳遞EpilepsyRBFOX3GABAergic neuronsHippocampusNeurodevelopmentExcitation/inhibition balanceNeuronal circuitrySynaptic transmission