CC3通过调控Olig1入核抑制OPC分化和髓鞘形成与再生

Myelin structure is critical for the normal function of the central nervous system (CNS). Demyelination exists in a wide variety of CNS diseases that are currently no cure. Oligodendrocyte precursor cell (OPC) is the cell source of myelin formation (myelination) during development, as well as myelin repair (remyelination) in adult after damage. Differentiation of OPCs into mature oligodendrocytes (OLs) is a prerequisite for both developmental myelination and adult remyelination, while the impairment of this process has been strongly suggested to be a major reason for remyelination failure. Thus, a thorough understanding of the molecular mechanisms that control the OPC differentiation would be of great significance to develop remyelination enhancement therapies for demyelinating diseases. CC3, a 30-kDa HIV Tat-interacting protein also called TIP30 or HTIP2, is recently identified as a tumor suppressor with proapoptotic and anti-metastasis properties. While its role in tumor genesis has been repeatedly reported, little is known about its expression and effect in the CNS. Our preliminary data showed that CC3 is expressed in the OPC and can significantly inhibit the differentiation of OPC. What's more, we also found that CC3 can interact/bind with olig1, a transcription factor the highly involved in the control of in OPC maturation. We thus raise the working hypothesis that CC3 may interact/bind with olig1 and sequestrate it in the cytoplasm therefore blocking its nuclear translocation to inhibit OPC differentiation and myelination/remyelination. In this proposal, we aim 1) to further confirm or find out the effect of CC3 in OPC differentiation and myelination/remyelination in different models, including in vitro myelinating OPC-DRG co-culture and cuprizone induced demyelination animal model; 2) to further confirm the interaction between CC3 and olig1 and the molecular mechanisms of this interaction; 3) to found out whether CC3 can block the nuclear translocation of olig1 and whether this blockage is essential for the inhibitory effect of CC3 on OPC differeantiation; 4) to test if over expression or knock down of CC3 can delay or enhance the remyelination process or OPC differentiation in vivo using normal or transgenic mice; 5) to examine if abnormal high expression level of CC3 is accompanied by cytoplasm distribution of olig1 in OPC in the lesion site of human chronic demyelinating diseases. Various techniques including immunostaining, confocal imaging, immunobloting, LFB and toluidine blue staining, as well as electromicroscopy will be used to examine the OPC differentiation and the extent of myelination/remyelination. This study will reveal a novel role and mechanism of CC3 in control of OPC differentiation and myelination/remyelination, and provide new therapeutic targets and strategies for the treatment of demyelinating diseases.

中枢脱髓鞘性疾病广泛存在且缺乏有效治疗。少突胶质前体细胞（OPC）是中枢髓鞘形成和再生的细胞来源，其分化障碍是髓鞘再生失败的关键原因，但机制不明。CC3是一个被新近鉴定的肿瘤抑制因子，其在神经系统的表达和功能不清。本组前期实验发现CC3在OPC中表达并显著抑制后者分化，且与在该过程中起到重要调控的转录因子Olig1之间具有相互结合，据此提出CC3通过与Olig1的结合阻碍其入核转运从而抑制OPC分化和髓鞘形成与再生的研究假设。本研究将利用体外OPC分化、OPC-DRG细胞共培养、铜腙脱髓鞘、基因敲除小鼠等实验模型，结合人类脱髓鞘疾病相关标本，采用慢病毒介导的原代细胞和在体动物转染、基因突变、Co-IP、GST-Pull down等分子生物学方法，以细胞形态和生化分析、髓鞘染色、激光共聚焦成像、电镜观察等为检查手段，详细证明上述工作假设并探明内在的分子机制，为脱髓鞘疾病的治疗提供新的靶。

中枢脱髓鞘性疾病广泛存在且缺乏有效治疗。少突胶质前体细胞（OPC）是中枢髓鞘形成和再生的细胞来源，其分化障碍是髓鞘再生失败的关键原因，但机制不明。CC3是一个被新近鉴定的肿瘤抑制因子，其在神经系统的表达及作用不清。本组实验发现CC3在OPC中表达并显著抑制后者分化，且与在该过程中起到重要调控的转录因子Olig1之间具有相互结合，据此提出CC3通过与Olig1的结合阻碍其入核转运从而抑制OPC分化和髓鞘形成与再生的研究假设。本项目立项执行4年以来，本组利用体外OPC纯化培养的细胞分化模型、铜腙脱髓鞘、基因敲除小鼠等实验模型，结合人类脱髓鞘疾病相关标本，采用慢病毒介导的基因敲减和过表达、Co-IP等分子生物学方法，以细胞形态和生化分析、髓鞘染色、激光共聚焦成像等为检查手段，详细探求上述工作假设，发现和证实了CC3通过与OLIG1结合并将其滞留与细胞质、影响后者入核从而起到抑制OPC分化以及再髓鞘化的这一作用和机制。为脱髓鞘疾病的治疗提供了潜在的新靶点和治疗思路。本工作最终发表在了GLIA杂志。此外，项目执行几间，本人还展开了其他几项与本项目密切相关的、关于少突胶质细胞发育和功能的研究，并在《NATURE NEUROSCIENCE》以第一作者、《SCIENCE》以第六作者、《EXP.MOL.MED》为共同第一作者发表论著文章。以上文章皆标注了本基金（31471013）的资助。