Analysis of neural cell death using knock-in mouse model and organotypic culture system.

点击翻译按钮获取中文摘要

Familial central diabetes insipidus(FDI) is an autosomal dominant disease due to the mutation of arginine vasopressin(AVP) gene. The precursor form of AVP, prepro-AVP is encoded by the AVP gene on chromosome 20 and the precursor consists of the signal peptide, AVP, neurophysin and glycoprotein. Prepro-AVP is converted to pro-AVP by the removal of the signal peptide. Pro-AVP is packaged into vesicles and processed into AVP,NP, and glycoprotein during axonal transport from the supraoptic and paraventricular nuclei to the posterior pituitary.We investigated the detailed pathogenesis of the disease using organotypic culture of the hypothalamus and knock-in mouse as a FDI animal model. We selected the mutation which predicts the formation of Cys67 stop in the neurophysin moiety. Although all homozygous mice died within a week after delivery, heterozygous mice indicated polyuria and low content of AVP in the posterior pituitary around one month of age. Immunohistocheimcal staining density examined by antibodies against both normal and abnormal neurophysins in dendrite of AVP neuron decreased in the knock-in mice and the expression of AVP mRNA in the magnocellular nucleus also deteriorated after 3 months of age. These results indicate that dominant negative mechanism and/or the decrease of AVP expression might induce the phenotype of diabetes insipidus at early stage, and neural cell death in supraoptic and paraventricular nuclei is not primary cause at that time.On the other hand, we demonstrated the usefulness of hypothalamic organotypic culture to investigate the regulation of AVP expression by in situ hybridization in this study.We will examine more detailed pathogenesis of not only FDI but also the neuro-degenerative diseases using this animal model and the hypothalamic organotypic culture.