Differential gene expression in the activation and maturation of human monocytes

Differential-display or RNA fingerprint was applied to identify genes diffe rentially expressed in monocyte maturation induced by an immunomodulating p eptide on human peripheral blood mononuclear cells. Two unknown sequences ( 06c22 and 06c71) and p21 protein (cyclin dependent kinase inhibitor) were r epressed, and three genes activated: Cathepsin D, DRP2 (dihydropirimidinase related protein 2), and gp91phox (91-kDa subunit of citochrome b(558)), Ph enotype of evolving monocytes was analyzed by how cytometry and mRNA level of identified genes determined by reverse transcription-PCR. The expression pattern of identified genes seemed to correlate with different monocyte su bsets, monocyte-derived cells, and expected functional changes. After pepti de addition, immature monocytes were initially activated, increasing the ex pression of CD25, CD69, and HLA-DR markers. This was accompanied by repress ion of p21 and the two unknown sequences, along with the simultaneous activ ation of Cathepsin D and DRP2, Later, the differentiation marker CD16 rose, and gp91phox gene expression activated. Further maturation led certain mon ocytes to express marker CD23 and gp91phox expression to reach a maximum, w hile Cathepsin D and DRPS dropped to preactivation levels. Results reflect part of the evolution of immature monocytes toward macrophages and monocyte -derived dendritic cell precursors. (C) 2000 Academic Press.