Department of Pathology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
Department of Oral and Maxillofacial Surgery, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
Lab Invest. 2020 Dec;100(12):1551-1563. doi: 10.1038/s41374-020-0462-z. Epub 2020 Jul 8.
Purkinje cell protein 4/peptide 19 (PCP4/PEP19) is 7.6 kDa peptide originally found in Purkinje cells. PCP4/PEP19 is a differentiation maker of Purkinje cells, where it functions as an antiapoptotic factor. Cerebral neuronal cells also express PCP4/PEP19, which may be related to neuronal cell survival. However, evidence suggests that PCP4/PEP19 may also be involved in neuronal differentiation. Here, we investigated the effects of PCP4/PEP19 expression on neuronal differentiation by analyzing neurite outgrowth, and expression of neuronal differentiation markers in cultured human neuroblastoma M17 cells. When PCP4/PEP19 expression was reduced by siRNA-mediated knockdown, neurite outgrowth was significantly increased. Among many differentiation markers tested, expression of NeuroD1 was increased, while that of Ascl1 was decreased upon PCP4/PEP19 knockdown. Furthermore, luciferase reporter assays revealed that PCP4/PEP19 knockdown upregulated NeuroD1 and downregulated Ascl1 expression, at the transcriptional level. These results suggest a new function of PCP4/PEP19, which suppresses neurite outgrowth and neuronal differentiation through the regulation of NeuroD1 and Ascl1 expression in M17 cells. Furthermore, immunohistochemical studies showed that PCP4/PEP19 localizes in the nuclei of human neuroblastoma cells. Therefore, PCP4/PEP19 may also be an intranuclear negative regulator of neuronal differentiation and may thus be a potential therapeutic target to promote cellular differentiation in human neuroblastoma.
小脑浦肯野细胞蛋白 4/肽 19（PCP4/PEP19）是一种最初在小脑浦肯野细胞中发现的 7.6 kDa 肽。PCP4/PEP19 是小脑浦肯野细胞的分化标志物，作为一种抗凋亡因子发挥作用。脑神经元细胞也表达 PCP4/PEP19，这可能与神经元细胞存活有关。然而，有证据表明 PCP4/PEP19 也可能参与神经元分化。在这里，我们通过分析培养的人神经母细胞瘤 M17 细胞中的突起生长和神经元分化标志物的表达，研究了 PCP4/PEP19 表达对神经元分化的影响。当通过 siRNA 介导的敲低降低 PCP4/PEP19 的表达时，突起生长显著增加。在测试的许多分化标志物中，NeuroD1 的表达增加，而 Ascl1 的表达减少。此外，荧光素酶报告基因分析显示，PCP4/PEP19 敲低在转录水平上上调了 NeuroD1 并下调了 Ascl1 的表达。这些结果表明 PCP4/PEP19 的一个新功能，即通过调节 M17 细胞中的 NeuroD1 和 Ascl1 表达，抑制突起生长和神经元分化。此外，免疫组织化学研究表明 PCP4/PEP19 定位于人神经母细胞瘤细胞核内。因此，PCP4/PEP19 也可能是神经元分化的核内负调节剂，因此可能是促进人神经母细胞瘤细胞分化的潜在治疗靶点。
