中国神经再生研究(英文版) ›› 2016, Vol. 11 ›› Issue (2): 215-216.doi: 10.4103/1673-5374.177714

• 观点:神经损伤修复保护与再生 • 上一篇    下一篇

髓鞘形成和与再生需要的Tyro3受体GAS6的接合反应?

  

  • 收稿日期:2015-11-09 出版日期:2016-02-15 发布日期:2016-02-15
  • 基金资助:

    这项工作是由日本文部科学省和厚生劳动省支持。这项工作也得到了创新领域“科研(胶质大会)和武田科学基金会的支持。

Gas6-Tyro3 signaling is required for Schwann cell myelination and possible remyelination

Tomohiro Torii, Junji Yamauchi   

  1. Department of Pharmacology, National Center for Child Health and Development, Setagaya, Tokyo, Japan (Torii T, Yamauchi J)
    Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo , Japan (Yamauchi J)
  • Received:2015-11-09 Online:2016-02-15 Published:2016-02-15
  • Contact: Junji Yamauchi, Ph.D., yamauchi-j@ncchd.go.jp.

摘要:

脊椎动物的髓鞘会确保动作电位的快速传送以及长期保持轴突的完整性,但我们对髓鞘形成的分子机制仍知之甚少。最近的研究已经证明,髓鞘形成是由TAM酶家族:包括Tyro3(也称为BRT,DTK,RSE,Sky和TIF),Axl(也称为Ark,Tyro7,和UFO),以及Mer(也称为Eyk,Nym,和Tyro12)及其配体生长停滞特异性基因6(Gas6)调节。这三种TAM酶也会在大脑发育过程中表达,具体发生在白质内,并组成髓鞘化轴突。这些研究有助于鉴别与髓鞘少突胶质细胞和雪旺细胞相关的信号。众所周知的是TAM酶可以控制炎症反应、细胞增殖、细胞存活以及各种类型细胞的吞噬行为。作为其内源性配体,TAM酶能够识别蛋白S(PROS1)和Gas6,这两者在出生后会广泛表达在中枢神经系统中。有趣的是,最近的研究已经解释过Gas6信号通过磷脂酰肌醇3-激酶(PI3激酶)和上调2',3'-环状核苷酸3'-磷酸二酯酶控制少突胶质细胞存活,这是少突胶质细胞和髓鞘的一个标志。它还在少突胶质细胞髓鞘形成中起到重要作用。这些发现表明,TAM-Gas6信号通路促进神经系统中的少突胶质细胞髓鞘形成并支持免疫应答。此外,Gas6还促进双环己酮草酰二腙诱导的损伤后少突胶质细胞髓鞘再生,并且是少突胶质细胞存活的必要因素。总之,这些发现证明了TAM-Gas6信号通路在中枢神经系统少突胶质细胞中髓鞘形成/髓鞘再生和脱髓鞘的重要作用。然而,这一途径如何作用以及髓鞘形成过程中的分子机制仍是未知的。

Abstract:

Myelin plays important roles in vertebrates, ensuring the rapid propagation of action potentials and the long-term integrity of axons, but the molecular mechanisms of myelin formation remain poorly understood. Recent studies have demonstrated that myelination is regulated by the TAM family of enzymes, which consists of Tyro3 (also known as Brt, Dtk, Rse, Sky, and Tif), Axl (also known as Ark, Tyro7, and Ufo), and Mer (also known as Eyk, Nym, and Tyro12) along with its ligand growth arrest-specific gene 6 (Gas6). The three TAMs are also expressed in the brain during postnatal development, specifically, in the white matter, which consists of myelinated axons (Prieto et al. 2000). These studies are helping to identify the signals that are associated with myelination in oligodendrocytes and Schwann cells. It is well established that TAMs control inflammatory responses, cell proliferation, cell survival, and phagocytosis in cells of various types. As their endogenous ligands, the TAMs recognize protein S (PROS1) and Gas6, both of which are widely expressed in the central nervous system (CNS) after birth. Interestingly, recent works have explained that Gas6 signaling controls oligodendrocyte survival through phosphatidylinositol 3-kinase (PI3-kinase) and upregulates the expression of 2',3'-Cyclic-nucleotide 3'-phosphodiesterase (CNPase), which is known as a marker for oligodendrocyte and myelin. It also plays an important role in oligodendrocyte myelination. These findings indicate that the TAM-Gas6 signaling pathway promotes the myelination of oligodendrocytes in the nervous system as well as supporting immune responses. Moreover, Gas6 also promotes the remyelination of oligodendrocytes after cuprizone-induced injury and is necessary for oligodendrocyte survival. Taken together, these findings demonstrate that the TAM-Gas6 signaling pathway plays an important role in myelination/remyelination and demyelination by oligodendrocytes in the CNS. Yet the molecular mechanisms operating within this pathway and underlying the myelin formation process during development remain largely unknown. This review summarizes recent developments in our understanding of the necessity of Gas6-stimulated Tyro3 activation for Schwann cell myelination and/or remyelination.