Porcine Reproductive and Respiratory Syndrome Virus Infection Upregulates Negative Immune Regulators and T-Cell Exhaustion Markers
Porcine Reproductive and Respiratory Syndrome Virus Infection Upregulates Negative Immune Regulators and T-Cell Exhaustion Markers
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DOI：
10.1128/jvi.01052-21
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发表时间：
2021-11-01
影响因子：
5.4
通讯作者：
Vu, Hiep L. X.
中科院分区：
文献类型：
--
作者：
Chaudhari, Jayeshbhai;Liew, Chia-Sin;Vu, Hiep L. X.
猪肺泡巨噬细胞（PAM）是猪繁殖与呼吸综合征病毒（PRRSV）的主要靶细胞之一，但在感染的急性期，只有不到2%的PAM被病毒感染。为了比较分析PRRSV感染的PAM和保持未感染但暴露于感染的肺的炎性环境的旁观者PAM之间的宿主转录应答，用表达绿色荧光蛋白的PRRSV株（PRRSV-GFP）感染猪，并分选GFP（+）（PRRSV感染的）和GFP-（旁观者）细胞用于RNA测序（RNA-seq）。来自GFP（+）的约4.2%的RNA读段和来自GFP-PAM的0.06%的读段定位到PRRSV基因组，表明PRRSV感染的PAM与旁观者PAM有效分离。进一步的分析显示，与GFP-PAM相比，炎症细胞因子、干扰素刺激的基因和抗病毒基因在GFP（+）中高度上调。重要的是，与GFP-细胞相比，GFP（+）细胞中的负性免疫调节剂，包括NF-κ B抑制剂（NFKBIA、NFKBID、NFKBIZ和TNFAIP 3）和T细胞耗竭标志物（程序性死亡配体-1 [PD-L1]、PD-L2、白细胞介素-10 [IL-10]、IDO 1和转化生长因子β 2 [TGF β 2]）高度上调。通过使用原位杂交分析，肿瘤坏死因子（TNF）和NF-kB抑制剂的RNA转录检测PRRSV感染的PAM离体培养和肺切片的PRRSV感染的猪在急性感染阶段。总的来说，结果表明，PRRSV感染上调PAM中负性免疫调节因子和T细胞耗竭标志物的表达，以调节宿主免疫应答。我们的研究结果提供了进一步了解PRRSV的免疫发病机制。重要性猪繁殖与呼吸综合征病毒（Porcine reproductive and respiratory syndrome virus，PRRSV）在许多养猪国家广泛传播，给养猪业造成了巨大的经济损失。猪肺泡巨噬细胞（PAM）被认为是猪繁殖与呼吸综合征病毒复制的主要靶细胞。然而，只有不到2%的急性感染猪的PAM感染了病毒。在本研究中，我们利用表达绿色荧光蛋白的PRRSV株感染猪，并在感染的急性期从猪中分离感染和旁观者PAM进行转录组分析。与旁观者PAMS相比，PRRSV感染的PAMS显示出独特的基因表达谱，并包含许多独特的激活途径。有趣的是，在PRRSV感染的PAM中观察到NF-κ B信号传导抑制剂和T细胞耗竭分子的上调表达。我们的研究结果提供了额外的知识机制，繁殖与呼吸综合征采用调节宿主免疫系统。
Porcine alveolar macrophage (PAM) is one of the primary cellular targets for porcine reproductive and respiratory syndrome virus (PRRSV), but less than 2% of PAMs are infected with the virus during the acute stage of infection. To comparatively analyze the host transcriptional response between PRRSV-infected PAMs and bystander PAMs that remained uninfected but were exposed to the inflammatory milieu of an infected lung, pigs were infected with a PRRSV strain expressing green fluorescent protein (PRRSV-GFP), and GFP(+) (PRRSV infected) and GFP- (bystander) cells were sorted for RNA sequencing (RNA-seq). Approximately 4.2% of RNA reads from GFP(+) and 0.06% reads from GFP- PAMs mapped to the PRRSV genome, indicating that PRRSV-infected PAMs were effectively separated from bystander PAMs. Further analysis revealed that inflammatory cytokines, interferon-stimulated genes, and antiviral genes were highly up regulated in GFP(+) compared to GFP- PAMs. Importantly, negative immune regulators, including NF-kappa B inhibitors (NFKBIA, NFKBID, NFKBIZ, and TNFAIP3) and T-cell exhaustion markers (programmed death ligand-1 [PD-L1], PD-L2, interleukin-10 [IL-10], IDO1, and transforming growth factor beta 2 [TGFB2]) were highly upregulated in GFP(+) cells compared to GFP- cells. By using an in situ hybridization assay, RNA transcripts of tumor necrosis factor (TNF) and NF-kB inhibitors were detected in PRRSV-infected PAMs cultured ex vivo and lung sections of PRRSV-infected pigs during the acute stage of infection. Collectively, the results suggest that PRRSV infection upregulates expression of negative immune regulators and T-cell exhaustion markers in PAMs to modulate the host immune response. Our findings provide further insight into PRRSV immunopathogenesis.IMPORTANCE Porcine reproductive and respiratory syndrome virus (PRRSV) is widespread in many swine-producing countries, causing substantial economic losses to the swine industry. Porcine alveolar macrophage (PAM) is considered the primary target for PRRSV replication in pigs. However, less than 2% of PAMs from acutely infected pigs are infected with the virus. In the present study, we utilized a PRRSV strain expressing green fluorescent protein to infect pigs and sorted infected and bystander PAMs from the pigs during the acute stage of infection for transcriptome analysis. PRRSV-infected PAMs showed a distinctive gene expression profile and contained many uniquely activated pathways compared to bystander PAMs. Interestingly, upregulated expression of NF-kB signaling inhibitors and T-cell exhaustion molecules were observed in PRRSVinfected PAMs. Our findings provide additional knowledge on the mechanisms that PRRSV employs to modulate the host immune system.