title: Comparison of Gene Expression by Sheep and Human Blood Stimulated with the TLR4 Agonists Lipopolysaccharide and Monophosphoryl Lipid A.
abstract: BACKGROUND
  Animal models that mimic human biology are important for successful translation of basic science discoveries into the clinical practice. Recent studies in rodents have demonstrated the efficacy of TLR4 agonists as immunomodulators in models of infection. However, rodent models have been criticized for not mimicking important characteristics of the human immune response to microbial products. The goal of this study was to compare genomic responses of human and sheep blood to the TLR4 agonists lipopolysaccharide (LPS) and monophosphoryl lipid A (MPLA).
  
  
  METHODS
  Venous blood, withdrawn from six healthy human adult volunteers (~ 28 years old) and six healthy adult female sheep (~3 years old), was mixed with 30 μL of PBS, LPS (1μg/mL) or MPLA (10μg/mL) and incubated at room temperature for 90 minutes on a rolling rocker. After incubation, 2.5 mL of blood was transferred to Paxgene Blood RNA tubes. Gene expression analysis was performed using an Agilent Bioanalyzer with the RNA6000 Nano Lab Chip. Agilent gene expression microarrays were scanned with a G2565 Microarray Scanner. Differentially expressed genes were identified.
  
  
  RESULTS
  11,431 human and 4,992 sheep probes were detected above background. Among them 1,029 human and 175 sheep genes were differentially expressed at a stringency of 1.5-fold change (p<0.05). Of the 175 sheep genes, 54 had a known human orthologue. Among those genes, 22 had > 1.5-fold changes in human samples. Genes of major inflammatory mediators, such as IL-1, IL-6 and IL-8, TNF alpha, NF-kappaB, ETS2, PTGS2, PTX3, CXCL16, KYNU, and CLEC4E were similarly (>2-fold) upregulated by LPS and MPLA in both species.
  
  
  CONCLUSIONS
  The genomic responses of peripheral blood to LPS and MPLA in sheep are quite similar to those observed in humans, supporting the use of the ovine model for translational studies that mimic human inflammatory diseases and the study of TLR-based immunomodulators.
authors.affiliation: Department of Anesthesiology, the University of Texas Medical Branch, Galveston, TX, United States of America.
authors.forename: Perenlei
authors.initials: P
authors.lastname: Enkhbaatar
authors.affiliation: Department of Anesthesiology, the University of Texas Medical Branch, Galveston, TX, United States of America.
authors.forename: Christina
authors.initials: C
authors.lastname: Nelson
authors.affiliation: Department of Anesthesiology, the University of Texas Medical Branch, Galveston, TX, United States of America.
authors.forename: John R
authors.initials: JR
authors.lastname: Salsbury
authors.affiliation: Molecular Virology and Microbiology Core, Alkek Center for Metagenomics & Microbiome Research, Baylor College of Medicine, Houston, TX, United States of America.
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Carmical
authors.affiliation: GenUs BioSystems, Northbrook, IL, United States of America.
authors.forename: Karen E O
authors.initials: KE
authors.lastname: Torres
authors.affiliation: Shriners Hospital for Children, Galveston, TX, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Herndon
authors.affiliation: Department of Anesthesiology, the University of Texas Medical Branch, Galveston, TX, United States of America.
authors.forename: Donald S
authors.initials: DS
authors.lastname: Prough
authors.affiliation: Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, United States of America.
authors.forename: Liming
authors.initials: L
authors.lastname: Luan
authors.affiliation: Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, United States of America.
authors.forename: Edward R
authors.initials: ER
authors.lastname: Sherwood
mesh_terms: D000328:Adult; D000818:Animals; D001769:Blood / Q000187:drug effects* / Q000276:immunology; D005260:Female; D005453:Fluorescence; D005786:Gene Expression Regulation / Q000187:drug effects*; D059014:High-Throughput Nucleotide Sequencing / Q000379:methods; D006801:Humans; D008050:Lipid A / Q000031:analogs & derivatives* / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D012756:Sheep; D013045:Species Specificity; D051197:Toll-Like Receptor 4 / Q000819:agonists*
chemical_list: D008050:Lipid A; D008070:Lipopolysaccharides; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C048436:monophosphoryl lipid A