DNA microarray analyses of genes expressed differentially in 3T3-L1 adipocytes co-cultured with murine macrophage cell line RAW 264.7 in the presence of the toll-like receptor 4 ligand bacterial endotoxin

Yamashita Akiko

Soga Yoshihiko

Iwamoto Yoshihiro

Asano T.

Li Y.

Abiko Yoshimitsu

Nishimura Fusanori

International Journal of Obesity

Recent studies have suggested macrophages were integrated to adipose tissues to interact with adipocytes, thereby exacerbating inflammatory responses. Furthermore, both adipocytes and macrophages appear to express TLR-4, and free fatty acids may stimulate cells via 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. 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 24h stimulation with 1 ng/ml of E. 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) markedly up-regulated gene expressions associated with inflammation and/or angiogenesis, such as those of IL-6, MCP-1, RANTES and CXCL1/KC, in adipocytes. Furthermore, several genes associated with insulin resistance were differentially expressed. Up-regulations 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 up-regulate the expressions of many genes associated with inflammation and/or angiogenesis.

adipocyte-macrophage interaction

TLR-4; endotoxin

gene expression

microarray analyses

Medical sciences [ 490 ]

eng

Nature Publishing Group

Copyright (c) 2009 Nature Publishing Group

[ISSN] 0307-0565

[DOI] 10.1038/ijo.2008.153

[NCID] AA00680691

[DOI] http://dx.doi.org/10.1038/ijo.2008.153