York Sara B, Hurwitz Stephanie N, Liu Xia, Meckes David G
Florida State University College of Medicine, Department of Biomedical Sciences, Tallahassee, FL, 32306, USA.
Florida State University College of Medicine, Department of Biomedical Sciences, Tallahassee, FL, 32306, USA.
Virology. 2023 Apr;581:128-138. doi: 10.1016/j.virol.2023.02.012. Epub 2023 Mar 8.
Epstein-Barr virus (EBV) is a human herpesvirus that is associated with a multitude of cancers. The primary EBV oncogene latent membrane protein 1 (LMP1) is secreted from infected cancer cells in small extracellular vesicles (EVs). Additionally, the tetraspanin protein CD63 forms a complex with LMP1 and CD63 can be trafficked to EVs through a ceramide-dependent manner. Therefore, we hypothesize that ceramide is required for efficient packaging of LMP1 into small EVs. Following treatment with the neutral sphingomyelinase inhibitor GW4869, LMP1 cellular localization was disrupted and immunoblotting of EV lysates revealed a significant reduction in extracellular LMP1. NTA of EVs from the LCLs treated with GW4869 demonstrated a significant decrease in particle secretion. Additionally, ceramide inhibition resulted in enhanced LMP1-mediated NFkB activation in EV producing cells. Taken together, these data reveal a critical role for the lipid ceramide in LMP1 exosomal trafficking and the oncogenic signaling properties of the viral protein.
爱泼斯坦-巴尔病毒（EBV）是一种与多种癌症相关的人类疱疹病毒。EBV的主要致癌基因潜伏膜蛋白1（LMP1）从小细胞外囊泡（EVs）中的受感染癌细胞分泌出来。此外，四跨膜蛋白CD63与LMP1形成复合物，并且CD63可以通过一种神经酰胺依赖性方式转运到EVs中。因此，我们推测神经酰胺是LMP1有效包装到小EVs中所必需的。用中性鞘磷脂酶抑制剂GW4869处理后，LMP1的细胞定位被破坏，对EV裂解物的免疫印迹显示细胞外LMP1显著减少。对用GW4869处理的淋巴母细胞系的EVs进行纳米颗粒跟踪分析（NTA）表明颗粒分泌显著减少。此外，神经酰胺抑制导致在产生EV的细胞中LMP1介导的核因子κB（NFkB）激活增强。综上所述，这些数据揭示了脂质神经酰胺在LMP1外泌体转运以及病毒蛋白的致癌信号特性中的关键作用。
