Ceruloplasmin (Cp) is an important extracellular regulator of iron metabolism. We showed previously that it stimulates Reelin proteolytic processing and cell aggregation in cultures of developing neurons. Reelin is a secreted protein required for the correct positioning of neurons in the brain. It is cleaved in vivo into N-terminally-derived 300K and 180K fragments through incompletely known mechanisms. One of Reelin signaling targets is the actin-binding protein cofilin, the phosphorylation of which is diminished in Reelin-deficient mice. This work looked for in vivo evidence of a relationship between Cp, Reelin and neuronal organization during brain development by analyzing wild-type and Cp-null mice. Cp as well as the full-length, 300K and 180K Reelin species appeared together in wild-type brains at embryonic day (E) 12.5 by immunoblotting. In wild-type compared to Cp-null brains, there was more 300K Reelin from E12.5 to E17.5, a period characterized by extensive, radially directed neuronal migration in the cerebral cortex. Immunofluorescence labeling of tissue sections at E16.5 revealed the localization of Cp with radial glia and meningeal cells adjacent to Reelin-producing Cajal-Retzius neurons, underlining the proximity of Cp and Reelin. Cofilin phosphorylation was seen starting at E10.5–E12.5 and lasted longer until postnatal day 7 in wild-type than Cp-null mice. Finally, using CUX1 as a marker revealed defective accumulation of neurons in layers II/III in neonatal and adult Cp-null mice. These results combined with our earlier work point to a potentially new role of Cp in Reelin processing and signaling and neuronal organization in the cerebral cortex in vivo.

铜蓝蛋白（Cp）是铁代谢的重要细胞外调节剂。我们以前表明，它在发育中的神经元文化中刺激Reelin蛋白水解加工和细胞聚集。Reelin是大脑中神经元正确定位所需的一种分泌蛋白。它通过不完全已知的机制在体内裂解为N末端衍生的300K和180K片段。Reelin信号转导靶标之一是肌动蛋白结合蛋白cofilin，在Reelin缺陷型小鼠中其磷酸化减弱。这项工作在体内寻找通过分析野生型和无Cp的小鼠证明Cp，Reelin与神经发育过程中神经元组织之间的关系。Cp以及全长的300K和180K Reelin物种通过免疫印迹在胚胎第12.5天的野生型大脑中一起出现。与无Cp的大脑相比，在野生型中，从E12.5到E17.5有更多的300K Reelin，这一时期的特征是大脑皮层中广泛，径向定向的神经元迁移。在E16.5处组织切片的免疫荧光标记显示Cp定位于邻近产生Reelin的Cajal-Retzius神经元的放射状胶质细胞和脑膜细胞，突显了Cp和Reelin的接近性。与Cp-null小鼠相比，野生型中Cofilin的磷酸化作用始于E10.5-E12.5，持续至出生后第7天为止。最后，使用CUX1作为标记，可以发现新生鼠和成年Cp-null小鼠的II / III层中神经元的缺陷积累。这些结果与我们之前的工作相结合，表明Cp在Reelin加工和信号传导以及大脑皮层神经元组织中具有潜在的新作用。体内。