BACKGROUND: The frequency of allergic diseases is constantly rising. Dysregulated production of isotype E immunoglobulins is one of the key factors behind allergic reactions and its modulation is therefore an important target for pharmacological intervention. Natural products of the pseurotin family were reported to be inhibitors of IgE production in B-cells. Mechanistic details underlying these effects are however not well understood. PURPOSE: In the present study, we synthesized new analogs of natural pseurotins and extensively investigated their inhibitory effects on activation, proliferation and differentiation of B-cells, as well as on the production of IgE. STUDY DESIGN: Effects of two natural pseurotins (pseurotins A and D) and a collection of fully synthetic pseurotin analogs were studied on mouse B-cells stimulated by the combination of IL-4 and E. coli lipopolysaccharide. The IgE production was determined along with cell viability and cell proliferation. The phosphorylation of selected members of the STAT transcription factor family was subsequently investigated. Finally, the in vivo effect of pseurotin D on the ovalbumin-induced delayed type hypersensitivity response was tested in mice. RESULTS: We discovered that several fully synthetic pseurotin analogs were able to decrease the production of IgE in stimulated B-cells with potency comparable to that of pseurotins A and D. We found that the two natural pseurotins and the active synthetic analogs inhibited the phosphorylation of STAT3, STAT5 and STAT6 proteins in stimulated B-cells, resulting in the inhibition of B-cell proliferation and differentiation into the plasma cells. In vivo, pseurotin D decreased ovalbumin-induced foot pad edema. CONCLUSION: Our results advance the current mechanistic understanding of the pseurotin-induced inhibition of IgE production in B-cells by linking the effect to STAT signaling, and associated modulation of B-cell proliferation and differentiation. Together with our finding that structurally simpler pseurotin analogs were able to reproduce the effects of natural pseurotins, the presented work has implications for the future research on these secondary metabolites in the context of allergic diseases.
- MeSH
- Lymphocyte Activation drug effects MeSH
- B-Lymphocytes cytology drug effects physiology MeSH
- Cell Differentiation drug effects MeSH
- Edema chemically induced drug therapy MeSH
- Escherichia coli chemistry MeSH
- Phosphorylation drug effects MeSH
- Immunoglobulin E blood metabolism MeSH
- Immunoglobulin M blood metabolism MeSH
- Lipopolysaccharides pharmacology MeSH
- Mice, Inbred C57BL MeSH
- Ovalbumin toxicity MeSH
- Plasma Cells cytology physiology MeSH
- Pyrrolidinones chemistry pharmacology MeSH
- STAT Transcription Factors metabolism MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Natural pseurotins, secondary metabolites of fungi, commonly produced by various species such as Aspergillus flavus with suggested significant biological effects. However, little is known about effects of pseurotins on immune system functions. METHODS: Effects of pseurotin A and D on proliferation and viability of macrophage RAW 264.7 cells were evaluated together with mitochondrial respiration and glycolysis. Macrophage response to lipopolysaccharide was analyzed based on determination of nitric oxide (NO) production, expression of inducible NO synthase (iNOS), interleukin 6 (IL-6) and tumor necrosis factor production. Activation of selected signaling pathways, particularly STAT and MAPK, as well as expression of cyclins were determined. RESULTS: Natural pseurotins A and D in concentrations of up to 50 μM significantly inhibit proliferation of RAW 264.7 macrophages which was not complemented by induction of cell toxicity. The inhibition of cell proliferation was accompanied by downregulation of expression of cyclins and mitochondrial respiration via inhibition of particularly STAT3 phosphorylation. Both pseurotins significantly inhibited production of NO, expression of iNOS and IL-6 production. CONCLUSION: Our results advance the current mechanistic understanding of the pseurotin-induced inhibition of proliferation, metabolic respiration and functional responses in macrophages by linking the effect to JAK/STAT signaling pathway.
- MeSH
- Cyclins metabolism MeSH
- Lipopolysaccharides pharmacology MeSH
- Macrophages drug effects metabolism MeSH
- Inflammation Mediators metabolism MeSH
- Mitochondria drug effects metabolism MeSH
- Mice MeSH
- Cell Proliferation drug effects MeSH
- Pyrrolidinones pharmacology MeSH
- RAW 264.7 Cells MeSH
- Signal Transduction drug effects MeSH
- STAT3 Transcription Factor metabolism MeSH
- Inflammation prevention & control MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
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- Meeting Abstract MeSH
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- Meeting Abstract MeSH
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- Meeting Abstract MeSH
BACKGROUND: Pseurotins, a family of secondary metabolites of different fungi characterized by an unusual spirocyclic furanone-lactam core, are suggested to have different biological activities including the modulation of immune response. PURPOSE: Complex characterization of the effects of pseurotin D on human lymphocyte activation in order to understand the potential of pseurotin to modulate immune response in humans. METHODS: CD4+ and CD8+ T cells and CD19+ B cells isolated from human blood were activated by various activators simultaneously with pseurotin D treatment. The effects of pseurotin were tested on the basis of changes in cell viability, apoptosis, activation of signal transducers and activators of transcription (STAT) signaling pathways, production of tumor necrosis factor (TNF)-α by T cells, expression of activation markers CD69 and CD25 on T cells and Human Leukocyte Antigen-DR isotype (HLA-DR) on B cells, and the differentiation markers CD20, CD27, CD38, and immunoglobulin (Ig) D on B cells. RESULTS: Pseurotin D significantly inhibited the activation of both CD4+ and CD8+ human T cells complemented by the inhibition of TNF-α production without significant acute toxic effects. The Pseurotin D-mediated inhibition of T-cell activation was accompanied by the induction of the apoptosis of T cells. This corresponded with the inhibited phosphorylation of STAT3 and STAT5. In human B cells, pseurotin D did not significantly inhibit their activation; however, it affected their differentiation. CONCLUSIONS: Our results advance the current mechanistic understanding of the pseurotin-induced inhibition of lymphocytes and suggest pseurotins as new attractive chemotypes for future research in the context of immune-modulatory drugs.
- MeSH
- Lymphocyte Activation drug effects MeSH
- Antigens, CD19 metabolism MeSH
- Apoptosis drug effects MeSH
- B-Lymphocytes drug effects immunology MeSH
- Cell Differentiation drug effects MeSH
- CD4-Positive T-Lymphocytes drug effects immunology MeSH
- CD8-Positive T-Lymphocytes drug effects immunology MeSH
- Adult MeSH
- Immunologic Factors pharmacology MeSH
- Cells, Cultured MeSH
- Middle Aged MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Pyrrolidinones pharmacology MeSH
- Signal Transduction drug effects MeSH
- Tumor Necrosis Factor-alpha metabolism MeSH
- Healthy Volunteers MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Adolescent MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Pseurotins, secondary metabolites of fungi, represent a group of bioactive natural products with newly recognized biological activities, including the modulation of specific immune response. However, the type of immune response affected by pseurotins and the mechanistic details underlying these effects are still not understood. Thus, the aim of the current study was to examine the effects of pseurotin D on delayed-type IV hypersensitivity (DTH) reaction induced by chicken ovalbumin in vivo and to examine the effects of pseurotin D on major types of leukocytes responsible for DTH development in vitro. Pseurotin D significantly decreased paw swelling, the major symptom of DTH, as well as the DTH-related production of pro-inflammatory cytokine IL-1β, IL-4, IL-6, IFN-γ and anti-inflammatory cytokine IL-10 in paws tissue, spleen enlargement, and DTH-related changes in leukocyte counts in peripheral blood. In vitro, pseurotin D mediated a decrease in the proliferation and differentiation of both Th1 and Th2 cells, as was concluded on the basis of the inhibition of the gene expressions of Gata3 and Tbx21 and the production of effector cytokines IFN-γ and IL-13 in vitro. Further, pseurotin D significantly inhibited the activation and differentiation of B cells, as was documented by the significant inhibition of B cell proliferation, CD138 expression, and IgE production. In conclusion, the results show the potential of pseurotin D to inhibit DTH reaction, this phenomenon involving the inhibition of the activation and differentiation of both T cells and B cells.
- MeSH
- Cytokines MeSH
- Interferon-gamma MeSH
- Humans MeSH
- Hypersensitivity, Delayed * drug therapy MeSH
- Th2 Cells MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
Chronic lymphocytic leukemia (CLL) is the most prevalent lymphoid malignancy in many geographical regions of the world. Pseurotin D, a secondary metabolite of fungi, represents a group of bioactive natural products with a newly ascribed range of interesting biological activities. The purpose of this study was to bring new insights into the mechanism behind the effects of pseurotin D on MEC-1 cells as a representative CLL cell line, with a particular focus on selected signaling pathways important in the proliferation of cells and targeting mitochondrial metabolism. Our results showed that pseurotin D was able to significantly inhibit the proliferation of MEC-1 cells and arrested them in the G2/M cell cycle phase. In addition, pseurotin D was able to induce apoptosis. We found that all of these effects were associated with a change in mitochondrial membrane potential and the production of mitochondrial reactive oxygen species (ROS). We showed for the first time that pseurotin D suppresses MEC-1 cell proliferation and induces apoptotic cell death via induction of the collapse of the mitochondria respiratory chain and the ROS-related caspase pathway. Our results show the pseurotins family as promising compounds which could serve as a basis for the development of new compounds in the treatment of lymphoma.
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- Journal Article MeSH
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- Meeting Abstract MeSH
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- Meeting Abstract MeSH
