Chauvet N, Apert C, Dumoulin A, Epelbaum J, Alonso G
INSERM U 336, University of Montpellier II, France.
J Comp Neurol. 1997 Jan 27;377(4):550-64.
Amyloid precursor protein (APP) is a transmembrane glycoprotein which is believed to promote neural cell adhesion, neural survival, and neuritogenesis. The present study was undertaken to determine whether APP could be detected within different types of astroglial cells present in the central nervous system (CNS) of neonatal or adult rats. The localization of this protein within glial cells was studied by using a monoclonal antibody (Mab22C11) that recognizes all APP isoforms and in addition cross-reacts with APP-like proteins. In the brain of neonatal rats, Mab22C11 immunostaining was associated with numerous elongated radial glia-like structures. In the intact brain and spinal cord of adult rats, Mab22C11 immunostaining was associated with (i) numerous neuron-like structures and (ii) glial structures immunostained for glial fibrillary acidic protein (GFAP) and/or vimentin, including tanycytes mostly located in the mediobasal hypothalamus, fibrous astrocytes located in the white matter and ependymocytes bordering the ventricles. On the other hand, all the GFAP-immunostained astrocytes located in the grey matter were Mab22C11 negative. In the lesioned brain and spinal cord of adult rats, Mab22C11 immunostaining was associated with intensely GFAP-immunostained reactive astrocytes located close to a surgical lesion, but not with those induced by Wallerian degeneration that appear at a distance from a lesion. Electron microscopic observations further indicated that in all these labeled astroglial cells, Mab22C11 immunostaining was mainly localized to the limiting plasma membrane and the membrane of intracytoplasmic cisternae and vesicles. These data indicate that Mab22C11 antibody induces strong immunostaining of specific astroglial cells of the neonatal and adult rat CNS that support axonal outgrowth, therefore suggesting that an APP-like protein associated with these cells participates in their axonal outgrowth promoting properties.
淀粉样前体蛋白（APP）是一种跨膜糖蛋白，据信它能促进神经细胞黏附、神经存活和神经突生成。本研究旨在确定在新生或成年大鼠中枢神经系统（CNS）中存在的不同类型星形胶质细胞内是否能检测到APP。通过使用一种单克隆抗体（Mab22C11）来研究该蛋白在胶质细胞内的定位，该抗体可识别所有APP同工型，此外还与APP样蛋白发生交叉反应。在新生大鼠的大脑中，Mab22C11免疫染色与许多细长的放射状胶质样结构相关。在成年大鼠完整的脑和脊髓中，Mab22C11免疫染色与（i）许多神经元样结构以及（ii）胶质纤维酸性蛋白（GFAP）和/或波形蛋白免疫染色的胶质结构相关，包括主要位于下丘脑内侧基底部的伸展细胞、位于白质中的纤维性星形胶质细胞以及脑室周围的室管膜细胞。另一方面，所有位于灰质中的GFAP免疫染色星形胶质细胞均为Mab22C11阴性。在成年大鼠受损的脑和脊髓中，Mab22C11免疫染色与靠近手术损伤部位的强烈GFAP免疫染色反应性星形胶质细胞相关，但与远离损伤部位出现的沃勒变性诱导的星形胶质细胞无关。电子显微镜观察进一步表明，在所有这些标记的星形胶质细胞中，Mab22C11免疫染色主要定位于限制质膜以及胞质内池和囊泡的膜上。这些数据表明，Mab22C11抗体可诱导新生和成年大鼠CNS中支持轴突生长的特定星形胶质细胞产生强烈免疫染色，因此表明与这些细胞相关的一种APP样蛋白参与了它们促进轴突生长的特性。
