Ogino Himari, Hisanaga Arisa, Kohno Takao, Kondo Yuta, Okumura Kyoko, Kamei Takana, Sato Tempei, Asahara Hiroshi, Tsuiji Hitomi, Fukata Masaki, Hattori Mitsuharu
Department of Biomedical Science, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Aichi 467-8603, Japan.
Department of Systems BioMedicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8510, Japan, and.
J Neurosci. 2017 Mar 22;37(12):3181-3191. doi: 10.1523/JNEUROSCI.3632-16.2017. Epub 2017 Feb 17.
The secreted glycoprotein Reelin regulates embryonic brain development and adult brain functions. It has been suggested that reduced Reelin activity contributes to the pathogenesis of several neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease; however, noninvasive methods that can upregulate Reelin activity have yet to be developed. We previously found that the proteolytic cleavage of Reelin within Reelin repeat 3 (N-t site) abolishes Reelin activity , but it remains controversial as to whether this effect occurs Here we partially purified the enzyme that mediates the N-t cleavage of Reelin from the culture supernatant of cerebral cortical neurons. This enzyme was identified as a disintegrin and metalloproteinase with thrombospondin motifs-3 (ADAMTS-3). Recombinant ADAMTS-3 cleaved Reelin at the N-t site. ADAMTS-3 was expressed in excitatory neurons in the cerebral cortex and hippocampus. N-t cleavage of Reelin was markedly decreased in the embryonic cerebral cortex of ADAMTS-3 knock-out (KO) mice. Importantly, the amount of Dab1 and the phosphorylation level of Tau, which inversely correlate with Reelin activity, were significantly decreased in the cerebral cortex of ADAMTS-3 KO mice. Conditional KO mice, in which ADAMTS-3 was deficient only in the excitatory neurons of the forebrain, showed increased dendritic branching and elongation in the postnatal cerebral cortex. Our study shows that ADAMTS-3 is the major enzyme that cleaves and inactivates Reelin in the cerebral cortex and hippocampus. Therefore, inhibition of ADAMTS-3 may be an effective treatment for neuropsychiatric and neurodegenerative disorders. ADAMTS-3 was identified as the protease that cleaves and inactivates Reelin in the cerebral cortex and hippocampus. ADAMTS-3 was expressed in the excitatory neurons of the embryonic and postnatal cerebral cortex and hippocampus. Cleavage by ADAMTS-3 is the major contributor of Reelin inactivation Tau phosphorylation was decreased and dendritic branching and elongation was increased in ADAMTS-3-deficient mice. Therefore, inhibition of ADAMTS-3 upregulates Reelin activity and may be a potential therapeutic strategy for the prevention or treatment of neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease.
分泌型糖蛋白Reelin调节胚胎脑发育和成体脑功能。有人提出，Reelin活性降低会导致多种神经精神疾病和神经退行性疾病的发病机制，如精神分裂症和阿尔茨海默病；然而，尚未开发出能上调Reelin活性的非侵入性方法。我们之前发现，Reelin重复序列3（N端位点）内的Reelin蛋白水解切割会消除Reelin活性，但这种效应是否发生仍存在争议。在这里，我们从大脑皮质神经元的培养上清液中部分纯化了介导Reelin N端切割的酶。该酶被鉴定为含血小板反应蛋白基序的解整合素和金属蛋白酶-3（ADAMTS-3）。重组ADAMTS-3在N端位点切割Reelin。ADAMTS-3在大脑皮质和海马体的兴奋性神经元中表达。在ADAMTS-3基因敲除（KO）小鼠的胚胎大脑皮质中，Reelin的N端切割明显减少。重要的是，与Reelin活性呈负相关的Dab1量和Tau磷酸化水平在ADAMTS-3 KO小鼠的大脑皮质中显著降低。条件性KO小鼠中，ADAMTS-3仅在前脑的兴奋性神经元中缺乏，其出生后大脑皮质中的树突分支和伸长增加。我们的研究表明，ADAMTS-3是大脑皮质和海马体中切割并使Reelin失活的主要酶。因此，抑制ADAMTS-3可能是治疗神经精神疾病和神经退行性疾病的有效方法。ADAMTS-3被鉴定为在大脑皮质和海马体中切割并使Reelin失活的蛋白酶。ADAMTS-3在胚胎期和出生后大脑皮质及海马体的兴奋性神经元中表达。ADAMTS-3的切割是Reelin失活的主要原因。在ADAMTS-3缺陷小鼠中，Tau磷酸化降低，树突分支和伸长增加。因此，抑制ADAMTS-3可上调Reelin活性，可能是预防或治疗神经精神疾病和神经退行性疾病（如精神分裂症和阿尔茨海默病）的潜在治疗策略。
