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

Antifungals influence the immune-related transcriptomic landscape of human monocytes after Aspergillus fumigatus infection

The heterogeneity of clinical responses to antifungals in aspergillosis is partially understood. We hypothesized that besides direct antifungal effects, these discrepancies may be related to different immunomodulatory profiles. Human THP-1 monocytes were coincubated in vitro with Aspergillus fumigatus and variable concentrations of voriconazole (0.5, 1 and 2 mg/l), caspofungin (1 and 2 mg/l), amphotericin B deoxycholate (0.25, 0.5 and 1 mg/l) and liposomal amphotericin B (1, 2 and 3 mg/l). After 6 h of coincubation, total cellular RNA was extracted, converted into cDNA, and transcription of 84 genes involved in antifungal immunity was measured through RT-qPCR. The presence of A. fumigatus was the main driver of the global immune-related transcriptomic response. After Aspergillus infection, thirty genes were upregulated, while 19 genes were downregulated. Discrepancies across antifungals were also evident; voriconazole-containing conditions showed similar reaction to natural infection, while the use of liposomal Amphotericin B significantly decreased the inflammatory response. Chemokines (notably CCL20 and CXCL2) and pro-inflammatory cytokines (IL1A, IL1B, IL23, G-CSF) exhibited the most pronounced differences across antifungals. Pattern recognition receptors and adaptor protein transcription were minimally affected. Protein–protein-interaction network analysis showed that IL23A played a dominant role in upregulated genes. Pathway enrichment analysis indicated that cytokine-cytokine receptor integration, TNF signaling pathways and Toll-like receptor pathways were highly involved. This exploratory study confirms the heterogeneous immunomodulatory role of antifungals. Overall, voriconazole appears to maintain an early pro-inflammatory response seen in natural infection. Assessment of immunomodulatory response with clinical response may provide a better rationale for differences observed across antifungals.

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.

Amphotericin B membrane action: role for two types of ion channels in eliciting cell survival and lethal effects

The formation of aqueous pores by the polyene antibiotic amphotericin B (AmB) is at the basis of its fungicidal and leishmanicidal action. However, other types of nonlethal and dose-dependent biphasic effects that have been associated with the AmB action in different cells, including a variety of survival responses, are difficult to reconcile with the formation of a unique type of ion channel by the antibiotic. In this respect, there is increasing evidence indicating that AmB forms nonaqueous (cation-selective) channels at concentrations below the threshold at which aqueous pores are formed. The main foci of this review will be (1) to provide a summary of the evidence supporting the formation of cation-selective ion channels and aqueous pores by AmB in lipid membrane models and in the membranes of eukaryotic cells; (2) to discuss the influence of membrane parameters such as thickness fluctuations, the type of sterol present and the existence of sterol-rich specialized lipid raft microdomains in the formation process of such channels; and (3) to develop a cell model that serves as a framework for understanding how the intracellular K(+) and Na(+) concentration changes induced by the cation-selective AmB channels enhance multiple survival response pathways before they are overcome by the more sustained ion fluxes, Ca(2+)-dependent apoptotic events and cell lysis effects that are associated with the formation of AmB aqueous pores.

Differential transcriptional profiles induced by amphotericin B formulations on human monocytes during response to hyphae of Aspergillus fumigatus

Amphotericin B formulations possess diverse immunomodulatory properties that may contribute to the activity of phagocytes against invasive aspergillosis. In this work we provide a novel set of data on different gene transcriptional profiles of monocytes exposed to the combination of Aspergillus fumigatus and amphotericin B formulations. We used pathway-specific microarray analysis, RT-PCR analysis and enzyme-linked immunosorbent assays to compare the effects of amphotericin B deoxycholate (DAMB) at 1 μg/ml and amphotericin B lipid complex (ABLC) at 5 μg/ml to assess gene expression of immune molecules of THP-1 cells exposed to A. fumigatus hyphae (AF) for 4 h. A. fumigatus hyphae at effector/target ratio 10/1 induced mostly chemotactic factors for monocyte recruitment. DAMB at 1 μg/ml in the presence or absence of AF induced the most pronounced changes in pro-inflammatory and chemokine gene expression, while ABLC under the same conditions caused less dramatic effect. There was a reciprocal response of increased expression of the genes encoding IL-1β and IL-20 and decreased expression of IL-10, IL-2 and IL-3 in response of monocytes to both the hyphae and antifungal agents. These results demonstrate that amphotericin B formulations exert differential effects on genes encoding pro-inflammatory molecules, immunoregulatory molecules and chemokines by human monocytes during response to A. fumigatus and that these molecules may affect antifungal activity.