title: Up-regulation of pro-inflammatory factors by HP-PRRSV infection in microglia: implications for HP-PRRSV neuropathogenesis.
abstract: Atypical porcine reproductive and respiratory syndrome (PRRS) caused by a highly pathogenic PRRS virus (HP-PRRSV) is characterized by high fever, high morbidity, high mortality, and associated with severe neurological symptoms. Microglia are the resident innate immune cells in central nervous system (CNS), and their activation has been implicated as an important contributor to the pathogenesis of CNS diseases. In the present study, we successfully cultured porcine microglia and demonstrated that microglia could support PRRSV infection and replication in vitro. We further showed that HP-PRRSV infection significantly up-regulated the key inflammatory factors including IL-1β, TNF-α, IL-6, IL-12, IL-8, CXCL10, MCP-1, CCL3, CCL4, and CCL5 in cultured microglia as well as in the CNS of HP-PRRSV-infected pigs. The transcription factors NF-κB and AP-1, which are widely reported to regulate cytokine and chemokine productions, were activated by HP-PRRSV infection in microglia. Meanwhile, we found that HP-PRRSV induced cellular ROS formation in microglia and ROS scavenger was proved to significantly abolish the activation of pro-inflammatory cytokines (IL-1β, TNF-α, IL-6, and IL-8), suggesting that ROS are crucial for pro-inflammatory gene production. Importantly, incubation with supernatants from HP-PRRSV-infected microglia cell culture remarkably induced SH-SY5Y neuroblastoma cell death. Collectively, these results showed that PRRSV infection induced cytokine and ROS up-regulation in microglia, which might contribute to neurotoxicity. These data have implications for us to understand the neuropathogenesis of HP-PRRSV in pigs.
authors.affiliation: State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China.
authors.forename: Xin-Xin
authors.initials: XX
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China.
authors.forename: Rong
authors.initials: R
authors.lastname: Quan
authors.affiliation: State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China.
authors.forename: Xue-Kun
authors.initials: XK
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China.
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.affiliation: Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, United States.
authors.forename: Jishu
authors.initials: J
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China; Department of Microbiology and Immunology, College of Biological Sciences, China Agricultural University, Beijing, 100193 China. Electronic address: whfeng@cau.edu.cn.
authors.forename: Wen-Hai
authors.initials: WH
authors.lastname: Feng
mesh_terms: D000818:Animals; D001921:Brain / Q000276:immunology / Q000503:physiopathology; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000633:toxicity; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism; D017628:Microglia / Q000276:immunology* / Q000821:virology*; D009474:Neurons / Q000187:drug effects; D009609:Nitrous Oxide / Q000378:metabolism; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D013552:Swine; D015854:Up-Regulation
chemical_list: D017077:Culture Media, Conditioned; D016207:Cytokines; D017382:Reactive Oxygen Species; D009609:Nitrous Oxide
keywords: Cytokine; HP-PRRSV; Microglia; Neuroinflammation; ROS