Herpes simplex virus type 1 latency-associated transcript inhibits apoptosis and promotes neurite sprouting in neuroblastoma cells following serum starvation by maintaining protein kinase B (AKT) levels.
Herpes simplex virus type 1 latency-associated transcript inhibits apoptosis and promotes neurite sprouting in neuroblastoma cells following serum starvation by maintaining protein kinase B (AKT) levels.
复制标题
DOI：
10.1099/vir.0.015719-0
复制
发表时间：
2010-04
期刊：
影响因子：
--
通讯作者：
Sumin Li;D. Carpenter;C. Hsiang;S. Wechsler;Clinton Jones
中科院分区：
文献类型：
--
作者：
Sumin Li;D. Carpenter;C. Hsiang;S. Wechsler;Clinton Jones
单纯疱疹病毒1型潜伏相关转录本(LAT)在潜伏感染的感觉神经元中大量表达。在小动物感染模型中，晚期缺失突变病毒株具有减少再激活的表型，表明LAT在HSV-1的潜伏期-再激活周期中发挥着重要作用。以往的研究表明，LAT的抗凋亡功能在调节潜伏期-再激活周期中具有重要作用，因为有三种不同的抗凋亡基因可以替代LAT。虽然LAT抑制caspase3的激活，但LAT抑制caspase3激活的信号通路尚未确定。在这项研究中，我们分析了血清饥饿后稳定表达LAT的小鼠神经母细胞瘤细胞(C1300)(DC-LAT6细胞)。正如预期的那样，DC-LAT6细胞在停用血清后对凋亡具有抵抗力。去血清后，DC-LAT6细胞中总的和磷酸化的AKT(蛋白激酶B)水平高于C1300细胞或稳定转染LAT启动子突变的细胞株(DC-DeltaLAT311)。AKT是一种促进细胞存活的丝氨酸/苏氨酸蛋白激酶。一种特异的AKT抑制剂降低了LAT和磷酸化的AKT水平的抗凋亡功能。去血清后，DC-LAT6细胞有更多的突起生长，并呈现分化形态。去血清后，神经元特异性核蛋白Neun在DC-LAT6细胞中大量表达，而在C1300细胞中不表达，进一步支持了LAT促进神经元样形态的概念。总之，这些研究表明，LAT直接或间接地维持了总的和磷酸化的AKT水平，这与细胞存活率的增加和成熟的神经元样形态有关。
The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is expressed abundantly in latently infected sensory neurons. LAT-deletion-mutant virus strains have reduced-reactivation phenotypes in small animal models of infection, demonstrating that LAT plays an important role in the latency-reactivation cycle of HSV-1. Previous studies demonstrated that the anti-apoptosis functions of LAT are important for regulating the latency-reactivation cycle because three different anti-apoptosis genes can substitute for LAT. Although LAT inhibits caspase 3 activation, the signalling pathway by which LAT inhibits caspase 3 activation was not identified. In this study, we analysed mouse neuroblastoma cells (C1300) that express LAT stably (DC-LAT6 cells) following serum starvation. As expected, DC-LAT6 cells were resistant to apoptosis following serum withdrawal. Levels of total and phosphorylated AKT (protein kinase B), a serine/threonine protein kinase that promotes cell survival, were higher in DC-LAT6 cells after serum withdrawal than in C1300 cells or a cell line stably transfected with a LAT promoter mutant (DC-DeltaLAT311). A specific AKT inhibitor reduced the anti-apoptosis functions of LAT and phosphorylated AKT levels. After serum withdrawal, more DC-LAT6 cells sprouted neurites and exhibited a differentiated morphology. NeuN (neuronal nuclei), a neuron-specific nuclear protein, was expressed abundantly in DC-LAT6 cells, but not C1300 cells, after serum withdrawal, further supporting the concept that LAT enhanced neuronal-like morphology. Collectively, these studies suggested that LAT, directly or indirectly, maintained total and phosphorylated AKT levels, which correlated with increased cell survival and mature neuronal-like morphology.