Porcine reproductive and respiratory syndrome virus (PRRSV) is a causative pathogen of PRRS, one of the most economically disastrous swine diseases. Non-structural protein 1 (NSP1) of PRRSV consists of NSP1α and NSP1β which exhibit papain like cysteine protease activity. Recent evidence demonstrates that PRRSV NSP1 may be participated in modulating host immunity, but very few host proteins were discovered as targets for NSP1. In this study, we used RNA-seq to investigate the functional role of PRRSV NSP1 in porcine alveolar macrophages, 3D4/31 cells. Compared to empty vector (mock) transfectant, NSP1, NSP1α, and NSP1β expressing 3D4/31 cells displayed a total of 60 genes, 63 genes, and 80 genes as differentially expressed genes (DEGs), respectively. Most of DEGs are involved in early inflammatory responses including interleukin (IL)-17 signaling pathway, chemokine signaling pathway, tumor necrosis factor (TNF)-α signaling pathway, and cell adhesion molecules. Interestingly, PRRSV NSP1 expression in 3D4/31 cells decreased mRNA transcripts of Fosb and Gdf15 known to be involved in host cell signaling or host cell protection during inflammation. Therefore, PRRSV NSP1 might block the signaling involved in host immune surveillance. Further study is required to define the mechanism on how PRRSV NSP1 protein represses mRNA transcripts of specific host genes.

猪繁殖与呼吸综合症病毒（PRRSV）是PRRS的病原体，PRRS是最经济的灾难性猪疾病之一。PRRSV的非结构蛋白1（NSP1）由NSP1α和NSP1β组成，它们具有木瓜蛋白酶样半胱氨酸蛋白酶的活性。最近的证据表明PRRSV NSP1可能参与调节宿主的免疫力，但是很少有宿主蛋白被发现是NSP1的靶标。在这项研究中，我们使用RNA序列研究PRRSV NSP1在猪肺泡巨噬细胞3D4 / 31细胞中的功能。与空载体（模拟）转染子相比，表达NSP1，NSP1α和NSP1β的3D4 / 31细胞分别显示了60个基因，63个基因和80个基因作为差异表达基因（DEG）。大多数DEG参与早期炎症反应，包括白介素（IL）-17信号通路，趋化因子信号通路，肿瘤坏死因子（TNF）-α信号通路和细胞粘附分子。有趣的是，PRRSV NSP1在3D4 / 31细胞中的表达降低了mRNA的转录Fosb和Gdf15已知在炎症过程中参与宿主细胞信号传导或宿主细胞保护。因此，PRRSV NSP1可能会阻止宿主免疫监视中涉及的信号传导。需要进一步的研究来确定PRRSV NSP1蛋白如何抑制特定宿主基因的mRNA转录的机制。