Reelin, an extracellular matrix protein, is secreted by Cajal-Retzius cells and plays crucial roles in the development of brain structures and neuronal functions. Reductions in Reelin cause the brain dysfunctions associated with mental disorders, such as schizophrenia. A recent genome-wide copy number variation analysis of Japanese schizophrenia patients identified a novel deletion in RELN encoding Reelin. To clarify the pathophysiological role of the RELN deletion, we developed transgenic mice carrying the RELN deletion (Reln-del) and found abnormalities in their brain structures and social behavior. In the present study, we performed an in vitro analysis of Reelin expression, intracellular Reelin signaling, and the morphology of primary cultured cortical neurons from wild-type (WT) and Reln-del mice. Reelin protein levels were lower in Reln-del neurons than in WT neurons. Dab1 expression levels were significantly higher in Reln-del neurons than in WT neurons, suggesting that Reelin signaling was decreased in Reln-del neurons. Reelin was mainly expressed in γ-aminobutyric acid (GABA)-ergic inhibitory neurons, but not in parvalbumin (PV)-positive neurons. A small proportion of Ca²⁺/calmodulin-dependent protein kinase II α subunit (CaMKIIα)-positive excitatory neurons also expressed Reelin. In comparisons with WT neurons, significant decreases were observed in neurite lengths and branch points as well as in the number of postsynaptic density protein 95 (PSD95) immunoreactive puncta in Reln-del neurons. A disintegrin and metalloproteinase with thrombospondin motifs-3 (ADAMTS-3) is a protease that inactivates Reelin by cleavage at the N-t site. The knockdown of ADAMTS-3 by short hairpin RNAs suppressed Reelin cleavage in conditioned medium and reduced Dab1 expression, indicating that Reelin signaling was enhanced in the primary cultured cortical neurons of WT and heterozygous Reln-del. Accordingly, the inhibition of ADAMTS-3 may be a potential candidate in the clinical treatment of schizophrenia by enhancing Reelin signaling in the brain.

Reelin 是一种细胞外基质蛋白，由 Cajal-Retzius 细胞分泌，在大脑结构和神经元功能的发育中起着至关重要的作用。Reelin 的减少会导致与精神障碍（例如精神分裂症）相关的大脑功能障碍。最近对日本精神分裂症患者的全基因组拷贝数变异分析发现了RELN编码 Reelin 中的一个新缺失。为了阐明RELN缺失的病理生理作用，我们开发了携带RELN缺失 ( Reln -del) 的转基因小鼠，并发现它们的大脑结构和社会行为异常。在本研究中，我们进行了体外来自野生型 (WT) 和Reln -del 小鼠的 Reelin 表达、细胞内 Reelin 信号传导和原代培养的皮质神经元形态的分析。Reelin- del神经元中的Reelin 蛋白水平低于WT 神经元。Dab1 表达水平在Reln -del 神经元中显着高于WT 神经元，表明 Reelin 信号在Reln -del 神经元中降低。Reelin 主要在 γ-氨基丁酸 (GABA) 能抑制神经元中表达，但不在小清蛋白 (PV) 阳性神经元中表达。少量Ca ²⁺/钙调蛋白依赖性蛋白激酶 II α 亚基 (CaMKIIα) 阳性兴奋性神经元也表达 Reelin。与 WT 神经元相比，在Reln-del神经元中观察到神经突长度和分支点以及突触后密度蛋白 95 (PSD95) 免疫反应性斑点的数量显着减少。具有血小板反应蛋白基序-3 (ADAMTS-3) 的去整合素和金属蛋白酶是一种蛋白酶，可通过在 Nt 位点切割使 Reelin 失活。短发夹 RNA 对 ADAMTS-3 的敲低抑制了条件培养基中 Reelin 的切割并降低了 Dab1 的表达，表明 Reelin 信号在 WT 和杂合Reln的原代培养皮层神经元中得到增强- 德尔。因此，通过增强大脑中的 Reelin 信号传导，ADAMTS-3 的抑制可能是精神分裂症临床治疗的潜在候选者。