Doucette R, Devon R
Department of Anatomy, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
Glia. 1995 Feb;13(2):130-40. doi: 10.1002/glia.440130206.
The primary olfactory pathway contains non-myelinating glial cells, called ensheathing cells, that exhibit a variety of phenotypes depending on their immediate environment. In vivo, these cells normally possess a mixture of astrocyte- and Schwann cell-specific phenotypic features. When co-cultured with dorsal root ganglion neurons, their phenotype can become more like that of a myelinating Schwann cell. The objective of this study was to determine whether ensheathing cells would express a myelinating phenotype in culture in the absence of neurons but in the presence of cAMP analogues that are known to induce the expression of myelin associated molecules in Schwann cell cultures. The ensheathing cell cultures were initiated using the nerve fiber layers of Theiler stage 23 rat olfactory bulb primordia and were fed for 1 day to 3 weeks with serum containing (1% or 10% FBS) or serum-free media to which was added different concentrations of dBcAMP (0.1 to 1 mM) or forskolin (10 microM). These cultures were double-labelled with a rabbit polyclonal antibody to S100 in combination with mouse anti-GAL-C (O1 and BRD1 hybridomas) or anti-MBP monoclonal antibodies. The remaining cultures were double-labeled with a rabbit polyclonal antibody to GFAP in combination with the BRD1 antibody. Treatment with dBcAMP or forskolin failed to induce ensheathing cells to express MBP regardless of the concentration. On the other hand, the treatment induced approximately one tenth of the cells to express GAL-C, and virtually all of the cells to express GFAP. These results indicate that although ensheathing cells can synthesize myelin associated molecules, the cAMP second messenger system appears to play a lesser role in controlling the expression of a myelinating phenotype in ensheathing cells than it does in Schwann cells.
主要嗅觉通路包含一种非髓鞘形成的神经胶质细胞，称为被膜细胞，其表现出多种取决于其周围环境的表型。在体内，这些细胞通常具有星形胶质细胞和雪旺氏细胞特异性表型特征的混合。当与背根神经节神经元共培养时，它们的表型可变得更类似于髓鞘形成的雪旺氏细胞。本研究的目的是确定在没有神经元但存在已知可诱导雪旺氏细胞培养物中髓鞘相关分子表达的环磷酸腺苷（cAMP）类似物的情况下，被膜细胞在培养中是否会表达髓鞘形成表型。使用第23期泰勒大鼠嗅球原基的神经纤维层开始进行被膜细胞培养，并在含有（1%或10%胎牛血清）的血清或添加了不同浓度的二丁酰环磷腺苷钙（dBcAMP，0.1至1 mM）或福司可林（10 microM）的无血清培养基中培养1天至3周。这些培养物用兔抗S100多克隆抗体与小鼠抗半乳糖脑苷脂（GAL-C，O1和BRD1杂交瘤）或抗髓磷脂碱性蛋白（MBP）单克隆抗体进行双重标记。其余培养物用兔抗胶质纤维酸性蛋白（GFAP）多克隆抗体与BRD1抗体进行双重标记。无论浓度如何，用dBcAMP或福司可林处理均未能诱导被膜细胞表达MBP。另一方面，该处理诱导约十分之一的细胞表达GAL-C，并且几乎所有细胞都表达GFAP。这些结果表明，尽管被膜细胞可以合成髓鞘相关分子，但cAMP第二信使系统在控制被膜细胞中髓鞘形成表型的表达方面似乎比在雪旺氏细胞中起的作用更小。
