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. CONCLUSIONS: Many modified genes are products regulated by the Nuclear Factor-kappaB and Mitogen Activated Protein Kinase pathways, suggesting MLIF involvement with these two major pathways for the modulation of the inflammation and immune responses.

Effect of zinc upon human and murine cell viability and differentiation.

Most zinc studies show its benefits or changes that coincide with its deficiency, but some have reported damages by supplements. In this work, the effects of zinc in different cell lines (U-937, human monocytes, and murine bone marrow cells) were analyzed. The cells were put in their specific culture medium either alone or with a stimulant [1-phorbol 12-myristate 13-acetate (PMA) for U-937 and monocytes, granulocyte macrophage colony stimulating factor (GM-CSF) for bone marrow cells]. These preparations, with or without zinc (0.05 to 1.0 mM), were incubated and microscopically analyzed on days 3, 9, and 11. The viability of all cells cultivated with 0.05 and 0.1 mM of zinc was similar to that of the controls without zinc (90%). With 1.0 mM of zinc, the viability diminished (p < 0.005) to 80% in U-937 and to 50% in monocytes and bone marrow cells; the number of cells increased in the three lines, but there was no differentiation. We conclude that the effects observed with different doses of zinc vary not only among the different species but also according to the time the cells were exposed to the metal. The same doses of zinc can have either a stimulatory or an inhibitory effect.

[beta-Endorphins and the male reproductive system]. / beta-Endorfinas y el aparato reproductor masculino.

In the antique Chinese culture, it was already known about opioide for therapeutic usage. On 1975, Hughes et al., identificated two endogen pentapetides with potent opiate activity Leu-enkephalin and Met-enkephalin, ever since beta-Endorphin have been considered involucrated in many biological functions. beta-Endorphin have found in testis, seminal vesicle and prostate in different species. It has been observed a paracrine effect between in Leydig and Sertoli cells and inhibit the basal release of LH in man by inhibiting its pulsatile discharge. In this paper is discussed, in a general way, localization and production sites of beta-Endorphin especially their participation in male reproductive tract-physiology. Finally, it is mentioned the experimental methodology to identify and quantify beta-Endorphin in blood plasma and semen.