Da Fonte Dillon F, Martyniuk Chris J, Xing Lei, Trudeau Vance L
Department of Biology, University of Ottawa, Ottawa, ON, Canada.
Department of Physiological Sciences, College of Veterinary Medicine, UF Genetics Institute, University of Florida, Gainesville, FL, United States.
Front Endocrinol (Lausanne). 2018 Mar 6;9:68. doi: 10.3389/fendo.2018.00068. eCollection 2018.
Radial glial cells (RGCs) are the main macroglia in the teleost brain and have established roles in neurogenesis and neurosteroidogenesis. They are the only brain cell type expressing aromatase B (), the enzyme that synthesizes estrogens from androgen precursors. There are few studies on the regulation of RGC functions, but our previous investigations demonstrated that dopamine stimulates expression in goldfish RGCs, while secretoneurin A (SNa) inhibits the expression of this enzyme. Here, we determine the range of proteins and cellular processes responsive to SNa treatments in these steroidogenic cells. The focus here is on SNa, because this peptide is derived from selective processing of secretogranin II in magnocellular cells embedded within the RGC-rich preoptic nucleus. Primary cultures of RGCs were treated (24 h) with 10, 100, or 1,000 nM SNa. By using isobaric tagging for relative and absolute quantitation and a Hybrid Quadrupole Obritrap Mass Spectrometry system, a total of 1,363 unique proteins were identified in RGCs, and 609 proteins were significantly regulated by SNa at one or more concentrations. Proteins that showed differential expression with all three concentrations of SNa included H1 histone, glutamyl-prolyl-tRNA synthetase, Rho GDP dissociation inhibitor γ, vimentin A2, and small nuclear ribonucleoprotein-associated protein. At 10, 100, and 1,000 nM SNa, there were 5, 195, and 489 proteins that were downregulated, respectively, whereas the number of upregulated proteins were 72, 44, and 51, respectively. Subnetwork enrichment analysis of differentially regulated proteins revealed that processes such as actin organization, cytoskeleton organization and biogenesis, apoptosis, mRNA processing, RNA splicing, translation, cell growth, and proliferation are regulated by SNa based on the proteomic response. Moreover, we observed that, at the low concentration of SNa, there was an increase in the abundance of proteins involved in cell growth, proliferation, and migration, whereas higher concentration of SNa appeared to downregulate proteins involved in these processes, indicating a dose-dependent proteome response. At the highest concentration of SNa, proteins linked to the etiology of diseases of the central nervous system (brain injuries, Alzheimer disease, Parkinson's disease, cerebral infraction, brain ischemia) were also differentially regulated. These data implicate SNa in the control of cell proliferation and neurogenesis.
放射状胶质细胞（RGCs）是硬骨鱼脑中主要的大胶质细胞，在神经发生和神经甾体生成中发挥着既定作用。它们是唯一表达芳香化酶B（）的脑细胞类型，该酶可将雄激素前体合成雌激素。关于RGC功能调节的研究较少，但我们之前的研究表明，多巴胺可刺激金鱼RGCs中的表达，而促分泌素A（SNa）则抑制这种酶的表达。在这里，我们确定了这些类固醇生成细胞中对SNa处理有反应的蛋白质和细胞过程的范围。这里重点关注SNa，因为这种肽是由富含RGC的视前核中嵌入的大细胞中分泌粒蛋白II的选择性加工产生的。用10、100或1000 nM SNa处理RGC的原代培养物（24小时）。通过使用相对和绝对定量的等压标记和混合四极杆轨道阱质谱系统，在RGCs中总共鉴定出1363种独特的蛋白质，并且在一种或多种浓度下，有609种蛋白质受到SNa的显著调节。在所有三种SNa浓度下均表现出差异表达的蛋白质包括H1组蛋白、谷氨酰 - 脯氨酰 - tRNA合成酶、Rho GDP解离抑制剂γ、波形蛋白A2和小核核糖核蛋白相关蛋白。在10、100和1000 nM SNa时，分别有5、195和489种蛋白质被下调，而上调蛋白质的数量分别为72、44和51种。对差异调节蛋白质的子网富集分析表明，基于蛋白质组学反应，肌动蛋白组织、细胞骨架组织和生物发生、细胞凋亡、mRNA加工、RNA剪接、翻译、细胞生长和增殖等过程受SNa调节。此外，我们观察到，在低浓度的SNa下，参与细胞生长、增殖和迁移的蛋白质丰度增加，而较高浓度的SNa似乎下调了参与这些过程的蛋白质，表明存在剂量依赖性蛋白质组反应。在最高浓度的SNa下，与中枢神经系统疾病（脑损伤、阿尔茨海默病、帕金森病、脑梗死、脑缺血）病因相关的蛋白质也受到差异调节。这些数据表明SNa参与细胞增殖和神经发生的控制。
