Molecular Mechanisms of Axonal Regeneration

描述(申请人提供)：哺乳动物中枢神经系统轴突再生的失败归因于髓鞘的恶劣环境和成熟神经元内在再生能力的减弱。切断背根神经节神经元的外周分支可获得较强的再生能力，使其能够在受损的脊髓背柱中再生其中心分支。三个转录因子ATF3、STAT3和Smad1的作用将通过RNA干扰和Sindbis病毒的过度表达来研究。通过对野生型、p75-/-、Troy-/-、NgR-/-小鼠或双突变小鼠的背根节和小脑颗粒细胞的分离神经元和外植体进行髓鞘抑制实验，研究p75和Troy、NgR1及其同系物NgR2和NgR3可能在髓鞘抑制中可能的多余作用。RNA干扰将用于多个基因敲除。上位性分析将被用来研究p75/NGR受体复合体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源性髓鞘抑制的机制。

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.