視神經一旦受損很難恢復。日本大阪大學和東北大學的一個聯合研究小組日前宣布,他們通過抑制神經細胞內某種酶的作用,令實驗鼠受損的視神經得以修復。
大阪大學教授山下俊英和東北大學教授高井俊行率領的研究小組發現,在神經細胞中發揮作用的一種蛋白酪氨酸磷酸酶SHP會妨礙神經再生。於是,他們設法抑制SHP發揮作用,結果顯示,促進神經生長蛋白質的功能可以隨之提高1.4倍。對視神經完全受損小鼠進行的實驗進一步證實,通過向小鼠眼球中注入SHP抑制劑,小鼠的視神經在兩周後可以得到修復。
山下俊英說,這一成果還可應用於中樞神經系統的再生,並將有助於開發神經系統修復新藥。
相關論文已刊登在新一期《歐洲分子生物學組織雜誌》(The EMBO Journal)上。(生物谷Bioon.com)
生物谷推薦原文出處:
The EMBO Journal doi:10.1038/emboj.2011.55
Myelin suppresses axon regeneration by PIR-B/SHP-mediated inhibition of Trk activity
Yuki Fujita, Shota Endo, Toshiyuki Takai and Toshihide Yamashita
Abstract
Paired immunoglobulin-like receptor B (PIR-B) partially mediates the regeneration-inhibiting effects of the myelin-derived protein Nogo, myelin-associated glycoprotein (MAG), and oligodendrocyte-myelin glycoprotein (OMgp). In this study, we report that inhibition of the PIR-B signaling cascades in neurons enhances axon regeneration in the central nervous system (CNS). Binding of MAG to PIR-B led to the association of PIR-B with tropomyosin receptor kinase (Trk) neurotrophin receptors. Src homology 2-containing protein tyrosine phosphatase (SHP)-1 and SHP-2, which were recruited to PIR-B upon MAG binding, functioned as Trk tyrosine phosphatases. Further, SHP-1 and SHP-2 inhibition reduced MAG-induced dephosphorylation of Trk receptors and abolished the inhibitory effect of MAG on neurite growth. Thus, PIR-B associated with Trk to downregulate basal and neurotrophin-regulated Trk activity through SHP-1/2 in neurons. Moreover, in vivo transfection of small interfering RNA (siRNA) for SHP-1 or SHP-2 induced axonal regeneration after optic nerve injury in mice. Our results thus identify a new molecular target to enhance regeneration of the injured CNS.