Distinct cytokine release profiles from human endothelial and THP-1 macrophage-like cells exposed to different amphotericin B formulations

Immunomodulatory properties of antifungal agents on phagocytic cells

Phagocytic cells, particularly neutrophils and monocytes/macrophages, are the first line and the most effective form of innate host defence against pathogenic fungi. During antifungal therapy these phagocytic cells are also exposed to antifungal agents. In the phagocyte-fungus-antifungal agent interplay, drugs may directly interact with phagocytes through specific pattern recognition receptors, leading to altered antifungal activities. Antifungal agents, through modulation of fungal virulence, may initiate different immune response programs in the phagocytes, leading to antifungal synergism/antagonism or up-regulation of gene expression for a pro-inflammatory response. Additionally, indirect modulation of phagocyte behavior by pretreatment of neutrophils, monocytes, and macrophages with cytokines and exposure to antifungal agents have shown promising findings for combined drug-cytokine therapy that may improve treatment of life-threatening fungal diseases. In this review, we discuss the main in vitro and in vivo immunomodulatory effects of antifungal agents on phagocytes in response to pathogenic fungi, as well as we address underlying immunopharmacologic mechanisms and their potential impact on clinical outcome.

ADAM9 inhibition increases membrane activity of ADAM10 and controls α-secretase processing of amyloid precursor protein

Prodomains of A disintegrin and metalloproteinase (ADAM) metallopeptidases can act as highly specific intra- and intermolecular inhibitors of ADAM catalytic activity. The mouse ADAM9 prodomain (proA9; amino acids 24-204), expressed and characterized from Escherichia coli, is a competitive inhibitor of human ADAM9 catalytic/disintegrin domain with an overall inhibition constant of 280 ± 34 nM and high specificity toward ADAM9. In SY5Y neuroblastoma cells overexpressing amyloid precursor protein, proA9 treatment reduces the amount of endogenous ADAM10 enzyme in the medium while increasing membrane-bound ADAM10, as shown both by Western and activity assays with selective fluorescent peptide substrates using proteolytic activity matrix analysis. An increase in membrane-bound ADAM10 generates higher levels of soluble amyloid precursor protein α in the medium, whereas soluble amyloid precursor protein β levels are decreased, demonstrating that inhibition of ADAM9 increases α-secretase activity on the cell membrane. Quantification of physiological ADAM10 substrates by a proteomic approach revealed that substrates, such as epidermal growth factor (EGF), HER2, osteoactivin, and CD40-ligand, are increased in the medium of BT474 breast tumor cells that were incubated with proA9, demonstrating that the regulation of ADAM10 by ADAM9 applies for many ADAM10 substrates. Taken together, our results demonstrate that ADAM10 activity is regulated by inhibition of ADAM9, and this regulation may be used to control shedding of amyloid precursor protein by enhancing α-secretase activity, a key regulatory step in the etiology of Alzheimer disease.

Post-acclimation transcriptome adjustment is a major factor in freezing tolerance of winter wheat

Cold-acclimated winter wheat plants were slowly frozen to -10 degrees C, and then the temperature was either maintained at -10 degrees C or was lowered further to -12 degrees C. Expression levels of a total of 423 genes were significantly altered in these treatments; genes upregulated outnumbered those downregulated by about a 9:1 ratio. Sixty-eight genes were upregulated at least fivefold in all freezing treatments; 17 of these 68 encoded transcription factors including C-repeat binding factor (Cbf), WRKY, or other Zn-finger proteins, indicating strong upregulation of genes involved in transcription regulation. Sixteen of the 68 highly upregulated genes encoded kinases, phosphatases, calcium trafficking-related proteins, or glycosyltransferases, indicating upregulation of genes involved in signal transduction. Six genes encoding chlorophyll a/b binding-like proteins were upregulated uniquely in response to the -12 degrees C treatment, suggesting a protective role of pigment-binding proteins in freezing stress response. Most genes responded similarly in the very freezing tolerant cultivar Norstar and in the moderately freezing tolerant Tiber, but some genes responded in opposite fashion in the two cultivars. These results showed that wheat crowns actively adapt as the temperature declines to potentially damaging levels, and genetic variation for this ability exists among cultivars.

Microarray analysis of amphotericin B-treated THP-1 monocytic cells identifies unique gene expression profiles among lipid and non-lipid drug formulations

The effects of deoxycholate amphotericin B (DAmB), amphotericin B lipid complex (ABLC), and amphotericin B colloidal dispersion (ABCD) on mRNA profiles from 218 genes in treated THP-1 monocytes were compared. Sixty-one genes were up-regulated and 8 were down-regulated by one or more of the AmB formulations. Fifty-three genes were up-regulated by DAmB while 24 and 18 genes were up-regulated by ABCD and ABLC, respectively. DAmB and ABCD up-regulated many pro-inflammatory genes, whereas ABLC did not. All three formulations up-regulated multiple categories of genes including the anti-apoptosis gene BIRC3 and the chemokine CXCL9 (MIG). Based on representative genes, DAmB activated more signaling pathways than ABCD or ABLC. Quantitative real time PCR confirmed array up-regulation of representative pro-inflammatory genes IL-8, CCL20 (MIP-3alpha), and CXCL2 (MIP-2alpha). Our study represents the first larger scale comparative gene expression profiling which may provide additional rationales for clinical side effects of each amphotericin B formulation.