UBE3A deficiency-induced autophagy is associated with activation of AMPK-ULK1 and p53 pathways.
UBE3A deficiency-induced autophagy is associated with activation of AMPK-ULK1 and p53 pathways.
复制标题
UBE3A 缺陷诱导的自噬与 AMPK-ULK1 和 p53 通路的激活相关。
DOI：
10.1016/j.expneurol.2023.114358
复制
发表时间：
2023
影响因子：
5.3
通讯作者：
Bi,Xiaoning
中科院分区：
文献类型：
--
作者：
Hao,Xiaoning;Sun,Jiandong;Zhong,Li;Baudry,Michel;Bi,Xiaoning
天使人综合征（AS）是一种由母体表达的dube3基因缺乏引起的神经发育障碍。UBE3A蛋白既是泛素-蛋白酶体系统（UPS）中的E3连接酶，也是类固醇激素受体的转录共激活因子。我们研究了UBE3A缺乏对AS小鼠小脑和COS1细胞自噬的影响。与野生型小鼠相比，AS小鼠小脑浦肯野细胞中LC3-和lamp2免疫阳性点的数量和大小增加。Western blot分析显示AS小鼠LC3I向LC3II的转化增加，正如自噬增加所预期的那样。活性AMPK及其底物之一ULK1（一种参与自噬起始的因子）的水平也增加。LC3与LAMP2共定位增加，p62水平降低，表明自噬通量增加。UBE3A缺乏还与细胞质中磷酸化p53水平降低和细胞核中磷酸化p53水平升高有关，这有利于自噬诱导。与对照siRNA处理的细胞相比，cox -1细胞中UBE3A siRNA敲低导致LC3免疫阳性点的大小和强度增加，LC3 II/I比值增加，证实了在as小鼠小脑中发现的结果。这些结果表明，UBE3A缺陷通过激活AMPK-ULK1通路和改变p53来增强自噬活性。
Angelman Syndrome (AS) is a neurodevelopmental disorder caused by deficiency of the maternally expressedUBE3Agene. The UBE3A proteins functions both as an E3 ligase in the ubiquitin-proteasome system (UPS), and as a transcriptional co-activator for steroid hormone receptors. Here we investigated the effects of UBE3A deficiency on autophagy in the cerebellum of AS mice and in COS1 cells. Numbers and size of LC3- and LAMP2-immunopositive puncta were increased in cerebellar Purkinje cells of AS mice, as compared to wildtype mice. Western blot analysis showed an increase in the conversion of LC3I to LC3II in AS mice, as expected from increased autophagy. Levels of active AMPK and of one of its substrates, ULK1, a factor involved in autophagy initiation, were also increased. Colocalization of LC3 with LAMP2 was increased and p62 levels were decreased, indicating an increase in autophagy flux. UBE3A deficiency was also associated with reduced levels of phosphorylated p53 in the cytosol and increased levels in nuclei, which favors autophagy induction. UBE3A siRNA knockdown in COS-1 cells resulted in increased size and intensity of LC3-immunopositive puncta and increased the LC3 II/I ratio, as compared to control siRNA-treated cells, confirming the results found in the cerebellum of AS mice. These results indicate that UBE3A deficiency enhances autophagic activity through activation of the AMPK-ULK1 pathway and alterations in p53.