微阵列分析长非编码 RNA 表达谱揭示了弓形虫诱导的宿主免疫信号负调控。

BACKGROUND: Toxoplasma gondii is an obligate intracellular protozoan parasite that can infect mammalian cells and thereby regulate host gene expression. The long non-coding RNAs (lncRNAs) have been demonstrated to be an important class of RNA molecules that regulate many biological processes, including host-pathogen interactions. However, the role of host lncRNAs in the response to T. gondii infection remains largely unknown. METHODS: We applied a microarray approach to determine the differential expression profiles of both lncRNAs and mRNAs in the human foreskin fibroblast (HFF) cells after T. gondii infection. The Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to reveal the potential functions of T. gondii-induced genes. Based on the co-expression networks of lncRNAs and immune-related genes, the role of NONSHAT022487 on the regulation of UNC93B1 related immune signaling was investigated by the knockdown and over-expression of lncRNA in human macrophage derived from the PMA-induced promonocytic cell line THP-1. RESULTS: Our data showed that 996 lncRNAs and 109 mRNAs in HFF cells were significantly and differentially expressed following T. gondii infection (fold change ≥ 5, P < 0.05). The results from the GO and KEGG pathway analyses indicated that the mRNAs with differential expression were mainly involved in the host immune response. Remarkably, we identified a novel lncRNA, NONSHAT022487, which suppresses the expression of the immune-related molecule UNC93B1. After T. gondii infection, NONSHAT022487 impaired the secretion of the cytokines IL-12, TNF-α, IL-1β and IFN-γ by downregulating UNC93B1 expression in human macrophage cells. CONCLUSIONS: Our study identified infection-induced lncRNA expression as a novel mechanism by which the Toxoplasma parasite regulates host immune signaling, which advances our understanding of the interaction of T. gondii parasites and host cells.

背景：刚地弓形虫是一种专性细胞内的原生动物寄生虫，能够感染哺乳动物细胞，从而调节宿主基因表达。长链非编码 RNA（lncRNA）已被证明是一类重要的 RNA 分子，能够调节包括宿主-病原体相互作用在内的许多生物学过程。然而，宿主 lncRNA 在宿主对弓形虫感染的反应中的作用在很大程度上仍是未知的。

方法：我们应用微阵列方法来确定人包皮成纤维细胞（HFF）在弓形虫感染后 lncRNA 和 mRNA 的差异表达谱。通过基因本体论（GO）和京都基因与基因组百科全书（KEGG）通路分析来揭示弓形虫诱导基因的潜在功能。根据 lncRNA 和免疫相关基因的共表达网络，通过在人巨噬细胞中转染 lncRNA 的敲低和过表达实验，研究 NONSHAT022487 对 UNC93B1 相关免疫信号通路的调节作用。人巨噬细胞来源于 PMA 诱导的单核前体细胞系 THP-1。

结果：我们的数据显示，在 HFF 细胞中，有 996 个 lncRNA 和 109 个 mRNA 在弓形虫感染后显著差异表达（倍数变化≥5，P<0.05）。GO 和 KEGG 通路分析的结果表明，差异表达的 mRNAs 主要参与宿主的免疫反应。值得注意的是，我们鉴定了一个新的 lncRNA，NONSHAT022487，它抑制了免疫相关分子 UNC93B1 的表达。在弓形虫感染后，NONSHAT022487 通过下调 UNC93B1 的表达，抑制了人巨噬细胞中细胞因子 IL-12、TNF-α、IL-1β 和 IFN-γ 的分泌。

结论：本研究鉴定了感染诱导的 lncRNA 表达，这是弓形虫寄生虫调节宿主免疫信号的一种新机制，加深了我们对弓形虫寄生虫与宿主细胞相互作用的理解。