Laboratory of Molecular Virology, School of Systems Biology, George Mason University, Manassas, VA, USA.
Center for Applied Proteomics and Molecular Medicine, George Mason University, Manassas, VA, USA.
Retrovirology. 2021 Feb 23;18(1):6. doi: 10.1186/s12977-021-00550-8.
The Human T-cell Lymphotropic Virus Type-1 (HTLV-1) is a blood-borne pathogen and etiological agent of Adult T-cell Leukemia/Lymphoma (ATLL) and HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). HTLV-1 has currently infected up to 10 million globally with highly endemic areas in Japan, Africa, the Caribbean and South America. We have previously shown that Extracellular Vesicles (EVs) enhance HTLV-1 transmission by promoting cell-cell contact.
Here, we separated EVs into subpopulations using differential ultracentrifugation (DUC) at speeds of 2 k (2000×g), 10 k (10,000×g), and 100 k (100,000×g) from infected cell supernatants. Proteomic analysis revealed that EVs contain the highest viral/host protein abundance in the 2 k subpopulation (2 k > 10 k > 100 k). The 2 k and 10 k populations contained viral proteins (i.e., p19 and Tax), and autophagy proteins (i.e., LC3 and p62) suggesting presence of autophagosomes as well as core histones. Interestingly, the use of 2 k EVs in an angiogenesis assay (mesenchymal stem cells + endothelial cells) caused deterioration of vascular-like-tubules. Cells commonly associated with the neurovascular unit (i.e., astrocytes, neurons, and macrophages) in the blood-brain barrier (BBB) showed that HTLV-1 EVs may induce expression of cytokines involved in migration (i.e., IL-8; 100 k > 2 k > 10 k) from astrocytes and monocyte-derived macrophages (i.e., IL-8; 2 k > 10 k). Finally, we found that EVs were able to promote cell-cell contact and viral transmission in monocytic cell-derived dendritic cell. The EVs from both 2 k and 10 k increased HTLV-1 spread in a humanized mouse model, as evidenced by an increase in proviral DNA and RNA in the Blood, Lymph Node, and Spleen.
Altogether, these data suggest that various EV subpopulations induce cytokine expression, tissue damage, and viral spread.
人类 T 细胞嗜淋巴细胞病毒 1 型（HTLV-1）是一种血源性病原体，也是成人 T 细胞白血病/淋巴瘤（ATLL）和 HTLV-1 相关脊髓病/热带痉挛性截瘫（HAM/TSP）的病因。HTLV-1 目前在全球已感染了多达 1000 万人，在日本、非洲、加勒比海和南美洲等地区高度流行。我们之前已经表明，细胞外囊泡（EVs）通过促进细胞间接触来增强 HTLV-1 的传播。
在这里，我们使用差速超速离心（DUC）从感染细胞上清液中以 2 k（2000×g）、10 k（10,000×g）和 100 k（100,000×g）的速度将 EVs 分离成亚群。蛋白质组学分析表明，EVs 在 2 k 亚群中含有最高的病毒/宿主蛋白丰度（2 k>10 k>100 k）。2 k 和 10 k 群体中含有病毒蛋白（即 p19 和 Tax）和自噬蛋白（即 LC3 和 p62），表明存在自噬体以及核心组蛋白。有趣的是，在血管生成测定（间充质干细胞+内皮细胞）中使用 2 k EV 会导致血管样小管恶化。血脑屏障（BBB）中与神经血管单元相关的常见细胞（即星形胶质细胞、神经元和巨噬细胞）显示，HTLV-1 EV 可能诱导与迁移相关的细胞因子的表达（即 IL-8；100 k>2 k>10 k）来自星形胶质细胞和单核细胞衍生的巨噬细胞（即 IL-8；2 k>10 k）。最后，我们发现 EV 能够促进单核细胞衍生的树突状细胞中的细胞间接触和病毒传播。来自 2 k 和 10 k 的 EV 增加了人源化小鼠模型中的 HTLV-1 传播，这表现为血液、淋巴结和脾脏中前病毒 DNA 和 RNA 的增加。
总的来说，这些数据表明，各种 EV 亚群诱导细胞因子表达、组织损伤和病毒传播。
