Berardi M, Hindelang C, Félix J M, Stoeckel M E
Laboratoire des Mécanismes Moléculaires de la Différenciation Cellulaire et de la Division-UPR 9005, Strasbourg, France.
Int J Dev Neurosci. 1999 Apr;17(2):121-30. doi: 10.1016/s0736-5748(98)00067-7.
L1 is a murine multidomain glycoprotein implicated in cell aggregation, fasciculation. neurite outgrowth and synaptogenesis. Laminin, a trimeric polypeptide, is implicated in neuronal survival, growth cone guidance, neurite outgrowth and cell differentiation. Laminin can also interact with the cell adhesion molecule L1. Their expressions were investigated from embryonic day 15 (E15) to adult in the rat hypophysis, and in adult neurohemal zones. Detected in the neural lobe from E17, the L1 immunoreactivity increased during prenatal development and persisted in adulthood mainly related to the neuropeptidergic fibers. Pituicytes were only labelled on the plasmalemma apposed to axons. In the intermediate lobe, L1 appeared at birth on folliculo-stellate cells extensions, constituting a network which densified during postnatal development. L1 is also expressed in all neurohemal areas on neuronal profiles. Laminin was clearly detectable in the hypophysis at E15 before the first blood vessels penetrate the Rathke pouch. At E20, all the basal membranes of the blood vessels were stained. In the intermediate lobe, a spotted laminin immunoreactivity was detected at E21. At this stage, we observed the staining of intercellular spaces and the intracellular labelling of melanotrophs, concerning reticulum or vesicles. The staining of melanotrophs seemed to maintain during adulthood. In contrast with blood vessels of the adult cerebral tissue, adult capillaries of the neural lobe and the others neuro-hemal zones were intensely labelled with the anti-laminin antibody. These results suggest that neurite outgrowth and neurite guidance could be promoted by L1 and laminin in the neurointermediate lobe. The "intercellular tunnels" could also be an important guidance cue for migrating cells in the intermediate lobe. These data also demonstrate that melanotrophic cells. secreting the laminin, have a role in the ontogenesis of the gland. Finally, we suggest that L1 and laminin can collaborate to reinforce "neurons-capillaries" interactions in neurohemal zones.
L1是一种与细胞聚集、成束、神经突生长和突触形成有关的小鼠多结构域糖蛋白。层粘连蛋白是一种三聚体多肽，与神经元存活、生长锥导向、神经突生长和细胞分化有关。层粘连蛋白还可与细胞粘附分子L1相互作用。研究了它们在大鼠垂体从胚胎第15天（E15）到成年期以及成年神经血区的表达情况。在神经叶中从E17开始检测到L1免疫反应性，在产前发育期间增加，并在成年期持续存在，主要与神经肽能纤维有关。垂体细胞仅在与轴突相对的质膜上被标记。在中间叶，L1在出生时出现在滤泡星状细胞的延伸部分，形成一个在出生后发育过程中致密化的网络。L1也在所有神经血区的神经元轮廓上表达。在第一批血管穿透拉特克囊之前的E15时，垂体中可清楚地检测到层粘连蛋白。在E20时，所有血管的基底膜都被染色。在中间叶，在E21时检测到斑点状层粘连蛋白免疫反应性。在此阶段，我们观察到细胞间隙的染色以及黑素细胞的细胞内标记，涉及内质网或囊泡。黑素细胞的染色在成年期似乎持续存在。与成人大脑组织的血管不同，神经叶和其他神经血区的成年毛细血管被抗层粘连蛋白抗体强烈标记。这些结果表明，L1和层粘连蛋白可促进神经中间叶的神经突生长和神经突导向。“细胞间通道”也可能是中间叶中迁移细胞的重要导向线索。这些数据还表明，分泌层粘连蛋白的黑素营养细胞在腺体的个体发生中起作用。最后，我们认为L1和层粘连蛋白可以协同加强神经血区的“神经元 - 毛细血管”相互作用。
