Gene expression profile during monocytes to macrophage differentiation

Macrophages play a critical role in the pathogenesis of many diseases, including rheumatoid arthritis, inflammatory bowel disease and atherosclerosis. Monocytes recruited into tissues from peripheral blood differentiate into macrophages. There is limited data concerning the global changes in the expression of genes during monocyte to macrophage, and how the patterns of change identify the mechanism contributing to differentiation or macrophage function. Employing the microarray technology, we examined the transcriptional profile of in vitro adherence-induced differentiation of primary human monocytes into macrophages. We found the significant up regulation of genes contributing to the functions of macrophage, including signature patterns defining the induction of genes contributing to immunity and defense; lipid, fatty acid and steroid metabolism; cell adhesion and; carbohydrate metabolism; amino acid metabolism and endocytosis. In contrast, a variety of transcription factors were down regulated during monocyte to macrophage differentiation, suggesting that transcriptional repression may be important for the transition from monocytes to macrophages. However, a limited number of transcription factors were up regulated, among these was C/EBPA, which may contribute to differentiation by regulating down stream genes, which a characteristic of differentiated macrophages. These observations suggest that examination of the transcriptional profile in monocytes and macrophages in patients may identify relevant therapeutic targets in diseases such as rheumatoid arthritis and atherosclerosis.

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Liu H, Shi B, Huang CC, Eksarko P, Pope RM