Department of Animal Science, North Carolina State University, Raleigh, NC 27607, USA.
Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Viruses. 2020 Nov 12;12(11):1299. doi: 10.3390/v12111299.
Porcine Reproductive and Respiratory Syndrome (PRRS) is a contagious viral (PRRSV) disease in pigs characterized by poor reproductive health, increased mortality, and reductions in growth rates. PRRSV is known to implement immuno-antagonistic mechanisms to evade detection and mute host responses to infection. To better understand the cellular immunosignature of PRRSV we have undertaken transcriptome and immunomodulatory studies in PRRSV-infected porcine alveolar macrophages (PAMs). We first used genome-wide transcriptome profiling (RNA-seq) to elucidate PRRSV-induced changes in the PAM transcriptome in response to infection. We found a number of cellular networks were altered by PRRSV infection, including many associated with innate immunity, such as, the NLRP3 inflammasome. To further explore the role(s) of innate immune networks in PRRSV-infected PAMs, we used an NLRP3-specific inhibitor, MCC950, to identify the potential functionality of the inflammasome during PRRSV replication. We found that PRRSV does quickly induce expression of inflammasome-associated genes in PAMs. Treatment of PAMs with MCC950 suggests NLRP3 inflammasome activation negatively impacts viral replication. Treatment of PAMs with cell culture supernatants from macrophages subjected to NLRP3 inflammasome activation (via polyinosinic-polycytidylic acid (poly I:C) transfection), prior to PRRSV infection resulted in significantly reduced viral RNA levels compared to PAMs treated with cell culture supernatants from macrophages subjected to NLRP3 inflammasome inhibition (MCC950 treatment/poly I:C transfection). This further supports a role for NLRP3 inflammasome activation in the innate macrophagic anti-PRRSV immune response and suggests that PRRSV is sensitive to the effects of NLRP3 inflammasome activity. Taken together, these transcriptome and immunoregulatory data highlight the complex changes PRRSV infection induces in the molecular immune networks of its cellular host.
猪繁殖与呼吸综合征（PRRS）是一种猪的传染性病毒性（PRRSV）疾病，其特征是生殖健康状况不佳、死亡率增加以及生长速度下降。PRRSV 已知采用免疫拮抗机制来逃避检测并使宿主对感染的反应沉默。为了更好地了解 PRRSV 的细胞免疫特征，我们对 PRRSV 感染的猪肺泡巨噬细胞（PAMs）进行了转录组和免疫调节研究。我们首先使用全基因组转录组谱分析（RNA-seq）阐明了 PRRSV 感染后 PAM 转录组中对感染的反应变化。我们发现 PRRSV 感染改变了许多细胞网络，包括与先天免疫相关的许多网络，例如 NLRP3 炎性小体。为了进一步探讨先天免疫网络在 PRRSV 感染的 PAMs 中的作用，我们使用了 NLRP3 特异性抑制剂 MCC950，以确定在 PRRSV 复制过程中炎性小体的潜在功能。我们发现 PRRSV 确实会迅速诱导 PAMs 中炎性小体相关基因的表达。用 MCC950 处理 PAMs 表明 NLRP3 炎性小体的激活会对病毒复制产生负面影响。在用 NLRP3 炎性小体激活（通过 polyinosinic-polycytidylic acid (poly I:C) 转染）的巨噬细胞的细胞培养上清液预处理 PRRSV 感染之前，用该上清液处理 PAMs 会导致病毒 RNA 水平与用细胞培养上清液处理 PAMs 相比明显降低从经 NLRP3 炎性小体抑制（MCC950 处理/poly I:C 转染）的巨噬细胞获得的上清液。这进一步支持 NLRP3 炎性小体的激活在先天巨噬细胞抗 PRRSV 免疫反应中的作用，并表明 PRRSV 对 NLRP3 炎性小体活性的影响敏感。总之，这些转录组和免疫调节数据突出了 PRRSV 感染在其细胞宿主的分子免疫网络中引起的复杂变化。
