Laboratory of Neurological Infections and Immunity, National Institute of Allergy and Infectious Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, Montana, USA.
Research Technologies Branch, National Institute of Allergy and Infectious Diseases, Division of Intramural Research, Rocky Mountain Laboratories, National Institutes of Health, Hamilton, Montana, USA.
J Biol Chem. 2023 Nov;299(11):105319. doi: 10.1016/j.jbc.2023.105319. Epub 2023 Oct 4.
Mis-folding of the prion protein (PrP) is known to cause neurodegenerative disease; however, the native function of this protein remains poorly defined. PrP has been linked with many cellular functions, including cellular proliferation and senescence. It is also known to influence epidermal growth factor receptor (EGFR) signaling, a pathway that is itself linked with both cell growth and senescence. Adult neural stem cells (NSCs) persist at low levels in the brain throughout life and retain the ability to proliferate and differentiate into new neural lineage cells. KO of PrP has previously been shown to reduce NSC proliferative capacity. We used PrP KO and WT NSCs from adult mouse brain to examine the influence of PrP on cellular senescence, EGFR signaling, and the downstream cellular processes. PrP KO NSCs showed decreased cell proliferation and increased senescence in in vitro cultures. Expression of EGFR was decreased in PrP KO NSCs compared with WT NSCs and additional supplementation of EGF was sufficient to reduce senescence. RNA-seq analysis confirmed that significant changes were occurring at the mRNA level within the EGFR signaling pathway and these were associated with reduced expression of mitochondrial components and correspondingly reduced mitochondrial function. Metabolomic analysis of cellular energy pathways showed that blockages were occurring at critical sites for production of energy and biomass, including catabolism of pyruvate. We conclude that, in the absence of PrP, NSC growth pathways are downregulated as a consequence of insufficient energy and growth intermediates.
朊病毒蛋白(PrP)的错误折叠已知会导致神经退行性疾病;然而,该蛋白质的天然功能仍未得到明确界定。PrP 与许多细胞功能有关,包括细胞增殖和衰老。它还已知会影响表皮生长因子受体(EGFR)信号通路,该通路本身与细胞生长和衰老都有关。成年神经干细胞(NSCs)在一生中一直以低水平存在于大脑中,并保持增殖和分化为新的神经谱系细胞的能力。先前的研究表明,PrP 的 KO 会降低 NSCs 的增殖能力。我们使用来自成年小鼠大脑的 PrP KO 和 WT NSCs 来研究 PrP 对细胞衰老、EGFR 信号通路以及下游细胞过程的影响。PrP KO NSCs 在体外培养中显示出增殖能力降低和衰老增加。与 WT NSCs 相比,PrP KO NSCs 中的 EGFR 表达降低,并且额外补充 EGF 足以减少衰老。RNA-seq 分析证实,EGFR 信号通路中的 mRNA 水平发生了显著变化,这与线粒体成分的表达降低以及相应的线粒体功能降低有关。细胞能量通路的代谢组学分析表明,在能量和生物量产生的关键部位发生了阻断,包括丙酮酸的分解代谢。我们得出结论,在没有 PrP 的情况下,由于能量和生长中间体不足,NSC 生长途径被下调。
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