Reelin,一种由Cajal-Retzius神经元在发育中的新皮质边缘层表达的糖蛋白,已经被广泛证明在大脑发育过程中发挥着重要作用,引导神经元迁移和从放射状神经胶质脱离。在成人生活中,然而,许多研究已经将Reelin表达与增强神经元可塑性相关联。尽管其在成人大脑中的作用机制尚不清楚,Reelin主要由成熟中间神经元的子集表达。这里,我们证实了成年大脑皮层中这个亚群的表型.我们发现这些成熟的中间神经元,虽然靠近,缺乏多唾液酸化神经细胞粘附分子(PSA-NCAM)表达,由成熟中间神经元亚群表达的分子,与大脑发育有关,也参与成人大脑的神经元可塑性。然而,在Piriform皮层的II层中,有高密度的细胞表达Reelin,其神经化学表型和连通性以前没有描述过。有趣的是,在这些Reelin表达细胞附近,在Piriform皮层的这一层中存在许多表达PSA-NCAM和双皮质素(DCX)的未成熟神经元亚群。这里,我们显示Reelin细胞表达神经元标记神经元核(NeuN),但是大多数神经元缺乏成熟的兴奋性或抑制性神经元的标记。对其形态的详细分析表明,这些细胞中的一些可能对应于半月神经元。有趣的是,我们发现,这些细胞中的大多数表达T-box脑1(TBR-1),该转录因子不仅在有丝分裂后的神经元中发现,而且在Cajal-Retzius细胞中发现。我们建议这些Reelin表达细胞在发育过程中的功能可能与Cajal-Retzius细胞相似,成年期通过Piriform皮层II中的载脂蛋白E受体2(ApoER2)和极低密度脂蛋白受体(VLDLR)在维持PSA-NCAM/DCX神经元的未成熟表型中发挥作用。
Reelin, a glycoprotein expressed by Cajal-Retzius neurons throughout the marginal layer of developing neocortex, has been extensively shown to play an important role during brain development, guiding neuronal migration and detachment from radial glia. During the adult life, however, many studies have associated Reelin expression to enhanced neuronal plasticity. Although its mechanism of action in the adult brain remains mostly unknown, Reelin is expressed mainly by a subset of mature interneurons. Here, we confirm the described phenotype of this subpopulation in the adult neocortex. We show that these mature interneurons, although being in close proximity, lack polysialylated neural cell adhesion molecule (PSA-NCAM) expression, a molecule expressed by a subpopulation of mature interneurons, related to brain development and involved in neuronal plasticity of the adult brain as well. However, in the layer II of Piriform cortex there is a high density of cells expressing Reelin whose neurochemical phenotype and connectivity has not been described before. Interestingly, in close proximity to these Reelin expressing cells there is a numerous subpopulation of immature neurons expressing PSA-NCAM and doublecortin (DCX) in this layer of the Piriform cortex. Here, we show that Reelin cells express the neuronal marker Neuronal Nuclei (NeuN), but however the majority of neurons lack markers of mature excitatory or inhibitory neurons. A detail analysis of its morphology indicates these that some of these cells might correspond to semilunar neurons. Interestingly, we found that the majority of these cells express T-box brain 1 (TBR-1) a transcription factor found not only in post-mitotic neurons that differentiate to glutamatergic excitatory neurons but also in Cajal-Retzius cells. We suggest that the function of these Reelin expressing cells might be similar to that of the Cajal-Retzius cells during development, having a role in the maintenance of the immature phenotype of the PSA-NCAM/DCX neurons through its receptors apolipoprotein E receptor 2 (ApoER2) and very low density lipoprotein receptor (VLDLR) in the Piriform cortex layer II during adulthood.