title: DNA microarray analyses of genes expressed differentially in 3T3-L1 adipocytes co-cultured with murine macrophage cell line RAW264.7 in the presence of the toll-like receptor 4 ligand bacterial endotoxin.
abstract: Recent studies have suggested that macrophages were integrated into adipose tissues to interact with adipocytes, thereby exacerbating inflammatory responses. Furthermore, both adipocytes and macrophages appear to express toll-like receptor-4 (TLR-4), and free fatty acids may stimulate cells through TLR-4. Herein, we analyzed genes differentially expressed in adipocytes when co-cultured with macrophages in the presence of a ligand for TLR-4, bacterial lipopolysaccharide (LPS). RAW264.7, a murine macrophage cell line and differentiated 3T3-L1 adipocytes were co-cultured using a transwell system. Genes differentially expressed in adipocytes were analyzed by the DNA microarray method following 4, 8, 12 and 24 h stimulation with 1 ng ml(-1) of Escherichia coli LPS. Randomly selected genes with high expressions were confirmed by quantitative methods at both the gene and the protein level. Co-culture of macrophages and adipocytes with a low LPS concentration (1 ng ml(-1)) markedly upregulated gene expressions associated with inflammation and/or angiogenesis, such as those of interleukin-6 (IL-6), MCP-1, RANTES and CXCL1/KC, in adipocytes. Furthermore, several genes associated with insulin resistance were differentially expressed. Upregulations of genes encoding MCP-1, RANTES and CXC/KC were confirmed by quantitative methods. These results suggest that ligands for TLR-4 stimulate both adipocytes and macrophages to upregulate the expressions of many genes associated with inflammation and/or angiogenesis.
authors.affiliation: Department of Dental Science for Health Promotion, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yamashita
authors.forename: Y
authors.initials: Y
authors.lastname: Soga
authors.forename: Y
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: T
authors.initials: T
authors.lastname: Asano
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: Y
authors.initials: Y
authors.lastname: Abiko
authors.forename: F
authors.initials: F
authors.lastname: Nishimura
mesh_terms: D041721:3T3-L1 Cells / Q000378:metabolism; D017667:Adipocytes / Q000276:immunology*; D000818:Animals; D002460:Cell Line / Q000378:metabolism; D004731:Endotoxins / Q000235:genetics / Q000276:immunology*; D015870:Gene Expression; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D046228:Microarray Analysis; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000276:immunology*; D015854:Up-Regulation
chemical_list: D004731:Endotoxins; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4