Department of Molecular Neurobiology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Ibaraki, 305-8575, Japan.
Pharmaceuticals and Medical Devices Agency, 3-3-2 Kasumigaseki, Chiyoda-Ku, Tokyo, 100-0013, Japan.
Sci Rep. 2017 Oct 23;7(1):13847. doi: 10.1038/s41598-017-14185-3.
Heparan sulfate (HS) has been implicated in a wide range of cell signaling. Here we report a novel mechanism in which extracellular removal of 6-O-sulfate groups from HS by the endosulfatases, Sulf1 and Sulf2, is essential for axon guidance during development. In Sulf1/2 double knockout (DKO) mice, the corticospinal tract (CST) was dorsally displaced on the midbrain surface. In utero electroporation of Sulf1/2 into radial glial cells along the third ventricle, where Sulf1/2 mRNAs are normally expressed, rescued the CST defects in the DKO mice. Proteomic analysis and functional testing identified Slit2 as the key molecule associated with the DKO phenotype. In the DKO brain, 6-O-sulfated HS was increased, leading to abnormal accumulation of Slit2 protein on the pial surface of the cerebral peduncle and hypothalamus, which caused dorsal repulsion of CST axons. Our findings indicate that postbiosynthetic desulfation of HS by Sulfs controls CST axon guidance through fine-tuning of Slit2 presentation.
硫酸乙酰肝素（HS）参与了广泛的细胞信号转导。在这里，我们报告了一种新的机制，即通过内切磺基转移酶 Sulf1 和 Sulf2 将 HS 上的 6-O-硫酸基团从细胞外去除，这对于发育过程中的轴突导向是必不可少的。在 Sulf1/2 双敲除（DKO）小鼠中，皮质脊髓束（CST）在中脑表面向背侧移位。在 DKO 小鼠的第三脑室沿放射状胶质细胞进行 Sulf1/2 的胚胎电穿孔转染，其中正常表达 Sulf1/2 mRNAs，可挽救 CST 缺陷。蛋白质组学分析和功能测试鉴定出 Slit2 是与 DKO 表型相关的关键分子。在 DKO 大脑中，6-O-硫酸化 HS 增加，导致 Slit2 蛋白在大脑脚和下丘脑的软脑膜表面异常积累，从而导致 CST 轴突的背侧排斥。我们的研究结果表明，Sulfs 通过 HS 的后生脱硫作用通过精细调节 Slit2 的呈现来控制 CST 轴突导向。
