Gene expression profiles of bone marrow cells from mice phenotype-selected for maximal or minimal acute inflammations: searching for genes in acute inflammation modifier loci.

Two mouse lines were phenotype-selected for maximum (AIRmax) or minimum (AIRmin) acute inflammation responses to polyacrylamide bead (Biogel) injection. These lines differ in terms of bone marrow granulopoiesis, neutrophil resistance to apoptosis, and inflammatory cytokine production during acute inflammation responses. We compared gene expression profiles in bone marrow cells (BMC) of AIRmax and AIRmin mice during acute inflammatory reactions. The BMC from femurs were recovered 24 hr after subcutaneous injections of Biogel. Global gene expression analysis was performed on CodeLink Bioarrays (36K genes) using RNA pools of BMC from both control and treated AIRmax and AIRmin mice. Differentially expressed genes were statistically established and the over-represented gene ontology biological process categories were identified. Upregulations of about 136 and 198 genes were observed in the BMC of Biogel-treated AIRmax and AIRmin mice, respectively, but 740 genes were found to be downregulated in AIRmin mice compared with 94 genes in AIRmax mice. The over-represented biological themes of the differently expressed genes among AIRmax and AIRmin mice represent inflammatory response, signal transduction, cell proliferation and immune cell chemotaxis. We were able to demonstrate a broad downmodulation of gene transcripts in BMC from AIRmin mice during acute inflammation, and significant differentially expressed genes colocalized with previously mapped regions for inflammation-related phenotypes in chromosomes 1, 3, 6 and 11.