Institute of Genetics, Division of Molecular Genetics, University of Bonn, 53117 Bonn, Germany.
J Neurosci. 2012 May 30;32(22):7499-518. doi: 10.1523/JNEUROSCI.0392-12.2012.
In this study, we have investigated the contribution of oligodendrocytic connexin47 (Cx47) and astrocytic Cx30 to panglial gap junctional networks as well as myelin maintenance and function by deletion of both connexin coding DNAs in mice. Biocytin injections revealed complete disruption of oligodendrocyte-to-astrocyte coupling in the white matter of 10- to 15-d-old Cx30/Cx47 double-deficient mice, while oligodendrocyte-to-oligodendrocyte coupling was maintained. There were no quantitative differences regarding cellular networks in acute brain slices obtained from Cx30/Cx47 double-null mice and control littermates, probably caused by the upregulation of oligodendrocytic Cx32 in Cx30/Cx47 double-deficient mice. We observed early onset myelin pathology, and ∼40% of Cx30/Cx47 double-deficient animals died within 42 to 90 d after birth, accompanied by severe motor impairments. Histological and ultrastructural analyses revealed severe vacuolization and myelination defects in all white matter tracts of the CNS. Furthermore, Cx30/Cx47 double-deficient mice exhibited a decreased number of oligodendrocytes, severe astrogliosis, and microglial activation in white matter tracts. Although less affected concerning motor impairment, surviving double-knock-out (KO) mice showed behavioral alterations in the open field and in the rotarod task. Vacuole formation and thinner myelin sheaths were evident also with adult surviving double-KO mice. Since interastrocytic coupling due to Cx43 expression and interoligodendrocytic coupling because of Cx32 expression are still maintained, Cx30/Cx47 double-deficient mice demonstrate the functional role of both connexins for interastrocytic, interoligodendrocytic, and panglial coupling, and show that both connexins are required for maintenance of myelin.
在这项研究中，我们通过在小鼠中删除两种连接蛋白编码 DNA，研究了少突胶质细胞连接蛋白 47（Cx47）和星形胶质细胞连接蛋白 30（Cx30）对神经胶质细胞缝隙连接网络以及髓鞘维持和功能的贡献。生物素标记注射显示，在 10-15 天大的 Cx30/Cx47 双缺失小鼠的白质中，少突胶质细胞-星形胶质细胞偶联完全被破坏，而少突胶质细胞-少突胶质细胞偶联得以维持。从 Cx30/Cx47 双缺失小鼠和对照同窝仔鼠获得的急性脑片中，细胞网络没有数量上的差异，这可能是由于 Cx30/Cx47 双缺失小鼠中少突胶质细胞 Cx32 的上调所致。我们观察到早发性髓鞘病理学，并且约 40%的 Cx30/Cx47 双缺失动物在出生后 42 至 90 天内死亡，伴有严重的运动障碍。组织学和超微结构分析显示，中枢神经系统所有白质束均存在严重的空泡化和髓鞘缺陷。此外，Cx30/Cx47 双缺失小鼠在白质束中表现出少突胶质细胞数量减少、严重的星形胶质细胞增生和小胶质细胞激活。尽管运动障碍受影响较小，但存活的双敲除（KO）小鼠在开阔场和旋转棒任务中表现出行为改变。在成年存活的双 KO 小鼠中也可见空泡形成和更薄的髓鞘鞘。由于 Cx43 表达引起的星形胶质细胞间偶联和 Cx32 表达引起的少突胶质细胞间偶联仍然存在，因此 Cx30/Cx47 双缺失小鼠证明了两种连接蛋白在星形胶质细胞间、少突胶质细胞间和神经胶质细胞间偶联中的功能作用，并且表明两种连接蛋白均对于维持髓鞘是必需的。
