PMID- 34379512 OWN - NLM STAT- MEDLINE DCOM- 20211220 LR - 20220414 IS - 1098-5514 (Electronic) IS - 0022-538X (Print) IS - 0022-538X (Linking) VI - 95 IP - 21 DP - 2021 Oct 13 TI - Porcine Reproductive and Respiratory Syndrome Virus Infection Upregulates Negative Immune Regulators and T-Cell Exhaustion Markers. PG - e0105221 LID - 10.1128/JVI.01052-21 [doi] LID - e01052-21 AB - 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 upregulated in GFP(+) compared to GFP(-) PAMs. Importantly, negative immune regulators, including NF-kappaB 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 beta2 [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-kappaB 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-kappaB signaling inhibitors and T-cell exhaustion molecules were observed in PRRSV-infected PAMs. Our findings provide additional knowledge on the mechanisms that PRRSV employs to modulate the host immune system. FAU - Chaudhari, Jayeshbhai AU - Chaudhari J AD - Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. AD - School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. FAU - Liew, Chia-Sin AU - Liew CS AD - Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. FAU - Riethoven, Jean-Jack M AU - Riethoven JM AD - Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. AD - Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. AD - Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. FAU - Sillman, Sarah AU - Sillman S AD - School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. FAU - Vu, Hiep L X AU - Vu HLX AUID- ORCID: 0000-0001-8084-4358 AD - Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. AD - Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, USA. LA - eng GR - 2018-67015-28294/U.S. Department of Agriculture (USDA)/ GR - 1020749/U.S. Department of Agriculture (USDA)/ PT - Journal Article PT - Research Support, U.S. Gov't, Non-P.H.S. DEP - 20210811 PL - United States TA - J Virol JT - Journal of virology JID - 0113724 SB - IM MH - Animals MH - Gene Expression Profiling MH - Immunity/*genetics MH - Lung/immunology/pathology/virology MH - Macrophages, Alveolar/*immunology/*virology MH - Porcine Reproductive and Respiratory Syndrome/immunology/*physiopathology MH - Porcine respiratory and reproductive syndrome virus/*immunology MH - Sequence Analysis, RNA MH - Signal Transduction MH - Swine MH - T-Lymphocytes/*immunology MH - Transcriptome MH - Up-Regulation PMC - PMC8513478 OTO - NOTNLM OT - NF-kappaB inhibitors OT - PRRSV OT - RNA-seq OT - T-cell exhaustion OT - transcriptome EDAT- 2021/08/12 06:00 MHDA- 2021/12/21 06:00 PMCR- 2022/04/13 CRDT- 2021/08/11 17:13 PHST- 2021/08/12 06:00 [pubmed] PHST- 2021/12/21 06:00 [medline] PHST- 2021/08/11 17:13 [entrez] PHST- 2022/04/13 00:00 [pmc-release] AID - 01052-21 [pii] AID - jvi.01052-21 [pii] AID - 10.1128/JVI.01052-21 [doi] PST - ppublish SO - J Virol. 2021 Oct 13;95(21):e0105221. doi: 10.1128/JVI.01052-21. Epub 2021 Aug 11.