The effect of an anti-inflammatory pentapeptide produced by Entamoeba histolytica on gene expression in the U-937 monocytic cell line

Objective: Evaluate the Monocyte Locomotion Inhibitory Factor (MLIF) effect upon the expression of genes encoding human cytokines, receptors and related factors in the human cell line U-937. MLIF (Met-Gln-Cys-Asn-Ser) is an anti-inflammatory pentapeptide produced by Entamoeba histolytica that inhibits many human monocyte functions. Material and Methods: U-937 cell line cultured (24 hrs/RPMI). RNA extracted by Trizol method. 385 genes were analyzed on microarray membranes, complement by real-time RT-PCR and protein expression of some affected genes. Results: MLIF had a preferentially inhibitory effect on gene expression; four genes were over-expressed and 13 underexpressed in MILF vs. simple medium - constitutive expression. Three genes are over-expressed and 19 under-expressed in MLIF/PMA vs. PMA - induced expression. Conslusions: Many modified genes are products regulated by the Nuclear Factor-kappa B and Mitogen Activated Protein Kinase pathways, suggesting MLIF involvement with these two major pathways for the modulation of the inflammation and immune responses.