Lineberger Comprehensive Cancer Center, Department of Microbiology and Immunology, The University of North Carolina at Chapel Hillgrid.10698.36, Chapel Hill, North Carolina, USA.
Department of Biostatistics, Gillings School of Global Public Health, The University of North Carolina at Chapel Hillgrid.10698.36, Chapel Hill, North Carolina, USA.
mBio. 2022 Feb 22;13(1):e0347321. doi: 10.1128/mbio.03473-21. Epub 2022 Jan 4.
Kaposi's sarcoma-associated herpesvirus (KSHV)-associated primary effusion lymphomas (PEL) are traditionally viewed as homogenous regarding viral transcription and lineage of origin, but so far this contention has not been explored at the single-cell level. Single-cell RNA sequencing of latently infected PEL supports the existence of multiple subpopulations even within a single cell line. At most 1% of the cells showed evidence of near-complete lytic transcription. The majority of cells only expressed the canonical viral latent transcripts: those originating from the latency locus, the viral interferon regulatory factor locus, and the viral lncRNA nut-1/Pan/T1.1; however, a significant fraction of cells showed various degrees of more permissive transcription, and some showed no evidence of KSHV transcripts whatsoever. Levels of viral interleukin-6 (IL-6)/K2 mRNA emerged as the most distinguishing feature to subset KSHV-infected PEL. One newly uncovered phenotype is the existence of BCBL-1 cells that readily adhered to fibronectin and that displayed mesenchymal lineage-like characteristics. Latency is the defining characteristic of the and central to the tumorigenesis phenotype of Kaposi's sarcoma-associated herpesvirus (KSHV). KSHV-driven primary effusion lymphomas (PEL) rapidly develop resistance to therapy, suggesting tumor instability and plasticity. At any given time, a fraction of PEL cells spontaneously reactivate KSHV, suggesting transcriptional heterogeneity even within a clonal cell line under optimal growth conditions. This study employed single-cell mRNA sequencing to explore the within-population variability of KSHV transcription and how it relates to host cell transcription. Individual clonal PEL cells exhibited differing patterns of viral transcription. Most cells showed the canonical pattern of KSHV latency (LANA, vCyc, vFLIP, Kaposin, and vIRFs), but a significant fraction evidenced extended viral gene transcription, including of the viral IL-6 homolog, open reading frame K2. This study suggests new targets of intervention for PEL. It establishes a conceptual framework to design KSHV cure studies analogous to those for HIV.
卡波氏肉瘤相关疱疹病毒（KSHV）相关的原发性渗出性淋巴瘤（PEL）在病毒转录和起源谱系方面传统上被认为是同质的，但到目前为止，这一观点尚未在单细胞水平上得到探索。潜伏感染的 PEL 的单细胞 RNA 测序支持即使在单个细胞系中也存在多个亚群。只有不到 1%的细胞显示出接近完全裂解转录的证据。大多数细胞仅表达经典的病毒潜伏转录物：那些源自潜伏区、病毒干扰素调节因子区和病毒 lncRNA nut-1/Pan/T1.1 的转录物；然而，相当一部分细胞表现出不同程度的更许可的转录，有些细胞则根本没有 KSHV 转录物的证据。病毒白细胞介素 6（IL-6）/K2 mRNA 的水平成为区分 KSHV 感染的 PEL 的最显著特征。一个新发现的表型是存在易于附着在纤维连接蛋白上并表现出间充质谱系特征的 BCBL-1 细胞。潜伏是卡波氏肉瘤相关疱疹病毒（KSHV）的定义特征，也是卡波氏肉瘤肿瘤发生表型的核心。KSHV 驱动的原发性渗出性淋巴瘤（PEL）迅速对治疗产生耐药性，表明肿瘤不稳定和可塑性。在任何给定的时间，一部分 PEL 细胞自发重新激活 KSHV，这表明即使在最佳生长条件下的克隆细胞系中也存在转录异质性。本研究采用单细胞 mRNA 测序来探索 KSHV 转录的群体内变异性以及它与宿主细胞转录的关系。单个克隆的 PEL 细胞表现出不同的病毒转录模式。大多数细胞表现出 KSHV 潜伏的经典模式（LANA、vCyc、vFLIP、Kaposin 和 vIRFs），但相当一部分证据表明病毒基因转录的扩展，包括病毒白细胞介素 6 同源物、开放阅读框 K2。本研究为 PEL 提供了新的干预靶点。它为设计类似于 HIV 的 KSHV 治愈研究奠定了概念框架。
