Molecular Mechanisms of Axonal Regeneration

描述（由申请人提供）：哺乳动物中枢神经系统中轴突再生的失败归因于髓磷脂的不利环境和成熟神经元的固有再生能力的减弱。切断背根神经节神经元的外周支可使其在损伤的脊髓背柱中再生出中央支。利用RNA干扰技术和辛德毕斯病毒技术分别研究了ATF 3、Stat 3和Smad 1三种转录因子在急性基因沉默和过表达中的作用。为了剖析参与介导髓鞘抑制的分子途径，将通过对来自野生型、p75-/-、TROY-/-、NgR-/-小鼠或双突变小鼠的背根神经节和小脑颗粒细胞的解离神经元和外植体进行髓鞘抑制测定来研究p75和TROY、NgR 1及其同系物NgR 2和NgR 3的可能冗余作用。RNA干扰将用于多重敲减。将进行上位性分析以研究p75/NgR受体复合物和表皮生长因子受体（EGFR）之间的通路关系。这种理解有助于阐明内在生长状态和外在髓鞘抑制的机制。

DESCRIPTION (provided by applicant): The failure of axonal regeneration in mammalian central nervous system is attributed to hostile environment from myelin and the diminished instrinsic regenerative capacity of mature neurons. Axotomy of the peripheral branches of dorsal root ganglion neurons results in robust regeneration such that they can regenerate their central branches in lesioned spinal dorsal column. The roles of three transcription factors ATF3, Stat3 and Smad1 will be studied by using RNA interference for acute gene-silencing and Sindbis virus for overexpression. To dissect the molecular pathways involved in mediating myelin inhibition, the possibly redundant roles of p75 and TROY, NgR1 and its homologues NgR2 and NgR3 will be investigated by conducting myelin inhibition assays on dissociated neurons and explants of both dorsal root ganglion and cerebellar granule cells from wild-type, p75-/-, TROY-/-, NgR-/- mice or double mutant mice. RNA interference will be used for multiple knockdown. Epistasis analysis will be conducted to study the pathway relationships between the p75/NgR receptor complex and epidermal growth factor receptor (EGFR). Such understanding can help elucidate mechanisms of both intrinsic growth state and extrinsic myelin inhibition.