Implication of the proprotein convertase NARC-1/PCSK9 in the development of the nervous system
Implication of the proprotein convertase NARC-1/PCSK9 in the development of the nervous system
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DOI：
10.1111/j.1471-4159.2006.03928.x
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发表时间：
2006-08-01
影响因子：
4.7
通讯作者：
Seidah, Nabil G.
中科院分区：
文献类型：
--
作者：
Poirier, Steve;Prat, Annik;Seidah, Nabil G.
神经凋亡调节的转化酶-1/前蛋白转化酶枯草杆菌蛋白酶样-9 (NARC-1/PCSK9) 是一种前蛋白转化酶，最近被描述通过增强低密度脂蛋白受体 (LDLR) 的降解在胆固醇稳态中发挥重要作用，并可能在神经发育中发挥重要作用。在此，我们使用小鼠胚胎多能 P19 细胞和斑马鱼作为模型，研究了这种蛋白酶在中枢神经系统发育中的潜在参与。在视黄酸（RA）诱导 P19 细胞神经外胚层分化后进行时程定量 RT-PCR 分析。因此，NARC-1/PCSK9 的 mRNA 水平在分化第 2 天达到峰值，此后下降。相反，前蛋白转化酶枯草杆菌蛋白酶同工酶1/位点1蛋白酶和弗林蛋白酶的表达不受RA影响，而PC5/6和PC2的表达分别在分化期的前4天内和/或之后增加。这种模式不受胆固醇生成转录因子甾醇调节元件结合蛋白-2 的影响，该蛋白通常上调肝脏中 NARC-1/PCSK9 mRNA 水平。此外，在P19细胞中，RA治疗不影响内源性LDLR的蛋白水平。这与 NARC-1/PCSK9 在啮齿动物中枢神经系统（包括小脑）中的独特表达模式一致，其中 LDLR 不显着表达。整体原位杂交显示斑马鱼NARC-1/PCSK9在中枢神经系统和外周的表达模式与小鼠相似。斑马鱼 NARC-1/PCSK9 mRNA 的特异性敲低导致小脑神经元普遍解体和后脑-中脑边界丧失，导致胚胎在受精后约 96 小时死亡。这些数据支持 NARC-1/PCSK9 在 CNS 发育中的新作用，不同于在肝脏等胆固醇生成器官中的作用。
Neural apoptosis-regulated convertase-1/proprotein convertase subtilisin-kexin like-9 (NARC-1/PCSK9) is a proprotein convertase recently described to play a major role in cholesterol homeostasis through enhanced degradation of the low-density lipoprotein receptor (LDLR) and possibly in neural development. Herein, we investigated the potential involvement of this proteinase in the development of the CNS using mouse embryonal pluripotent P19 cells and the zebrafish as models. Time course quantitative RT-PCR analyses were performed following retinoic acid (RA)-induced neuroectodermal differentiation of P19 cells. Accordingly, the mRNA levels of NARC-1/PCSK9 peaked at day 2 of differentiation and fell off thereafter. In contrast, the expression of the proprotein convertases subtilisin kexin isozyme 1/site 1 protease and Furin was unaffected by RA, whereas that of PC5/6 and PC2 increased within and/or after the first 4 days of the differentiation period respectively. This pattern was not affected by the cholesterogenic transcription factor sterol regulatory element-binding protein-2, which normally up-regulates NARC-1/PCSK9 mRNA levels in liver. Furthermore, in P19 cells, RA treatment did not affect the protein level of the endogenous LDLR. This agrees with the unique expression pattern of NARC-1/PCSK9 in the rodent CNS, including the cerebellum, where the LDLR is not significantly expressed. Whole-mount in situ hybridization revealed that the pattern of expression of zebrafish NARC-1/PCSK9 is similar to that of mouse both in the CNS and periphery. Specific knockdown of zebrafish NARC-1/PCSK9 mRNA resulted in a general disorganization of cerebellar neurons and loss of hindbrain-midbrain boundaries, leading to embryonic death at similar to 96 h after fertilization. These data support a novel role for NARC-1/PCSK9 in CNS development, distinct from that in cholesterogenic organs such as liver.