title: Toll-Like Receptor 4 Promotes NO Synthesis by Upregulating GCHI Expression under Oxidative Stress Conditions in Sheep Monocytes/Macrophages.
abstract: Many groups of Gram-negative bacteria cause diseases that are harmful to sheep. Toll-like receptor 4 (TLR4), which is critical for detecting Gram-negative bacteria by the innate immune system, is activated by lipopolysaccharide (LPS) to initiate inflammatory responses and oxidative stress. Oxidation intermediates are essential activators of oxidative stress, as low levels of free radicals form a stressful oxidative environment that can clear invading pathogens. NO is an oxidation intermediate and its generation is regulated by nitric oxide synthase (iNOS). Guanosine triphosphate cyclohydrolase (GCHI) is the rate-limiting enzyme for tetrahydrobiopterin (BH4) synthesis, which is essential for the production of inducible iNOS. Previously, we made vectors to overexpress the sheep TLR4 gene. Herein, first generation (G1) of transgenic sheep was stimulated with LPS in vivo and in vitro, and oxidative stress and GCHI expression were investigated. Oxidative injury caused by TLR4 overexpression was tightly regulated in tissues. However, the transgenic (Tg) group still secreted nitric oxide (NO) when an iNOS inhibitor was added. Furthermore, GCHI expression remained upregulated in both serum and monocytes/macrophages. Thus, overexpression of TLR4 in transgenic sheep might accelerate the clearance of invading microbes through NO generation following LPS stimulation. Additionally, TLR4 overexpression also enhances GCHI activation.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Shoulong
authors.initials: S
authors.lastname: Deng
authors.affiliation: Laboratory of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China ; National Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Yu
authors.affiliation: National Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Baolu
authors.initials: B
authors.lastname: Zhang
authors.affiliation: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, China.
authors.forename: Yuchang
authors.initials: Y
authors.lastname: Yao
authors.affiliation: Laboratory of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
authors.forename: Zhixian
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Tianjin Institute of Animal Sciences, Tianjin 300112, China.
authors.forename: Jinlong
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Tianjin Institute of Animal Sciences, Tianjin 300112, China.
authors.forename: Xiaosheng
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Laboratory of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
authors.forename: Guoshi
authors.initials: G
authors.lastname: Liu
authors.affiliation: National Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yixun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Laboratory of Animal Genetics and Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China ; National Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Zhengxing
authors.initials: Z
authors.lastname: Lian
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000818:Animals; D030801:Animals, Genetically Modified / Q000378:metabolism; D016207:Cytokines / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D006136:GTP Cyclohydrolase / Q000097:blood / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity; D008264:Macrophages / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D008315:Malondialdehyde / Q000378:metabolism; D009000:Monocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012756:Sheep; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000098:Acetophenones; D016207:Cytokines; D008070:Lipopolysaccharides; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D051197:Toll-Like Receptor 4; D009569:Nitric Oxide; D008315:Malondialdehyde; C056165:acetovanillone; D052247:Nitric Oxide Synthase Type II; D006136:GTP Cyclohydrolase