ABSTRACT: Transcriptome and network analysis of amphotericin B and lactoferrin drug synergy in Saccharomyces cerevisiae reveals down-regulation of the stress response and dysregulation of zinc and iron homeostasis
Project description:Invasive fungal infections (IFIs) are difficult to treat. Few effective antifungal drugs are available and many have problems with toxicity, efficacy and drug-resistance. To overcome these challenges, existing therapies may be enhanced using more than one agent acting in synergy. Previously, we have found amphotericin B (AMB) and the iron chelator, lactoferrin (LF), were synergistic against Cryptococcus neoformans and Saccharomyces cerevisiae. This study investigates the mechanism of AMB+LF synergy, using RNA-seq and network analyses. Genes involved in iron homeostasis showed increased expression upon treatment with AMB alone. Unexpectedly, AMB+LF treatment did not lead to increased expression of iron or zinc homeostasis genes however we observed decreased expression of oxidative stress response genes. Addition of iron or zinc to AMB+LF treated cells did not rescue the synergy, supporting the likelihood that the mechanism of synergy involves more than iron and zinc chelation. We clustered genes based on patterns of co-expression and found by network analysis that many genes involved in iron and zinc homeostasis, which have dysregulated expression upon AMB+LF treatment, are targets of transcription factors Aft1p and Zap1p. Hypothesizing that these might play a key role in the synergistic response, knock-out mutants of Aft1 and Zap1 were tested for increased sensitivity to AMB and oxidative stress. Both mutants showed hypersensitivity towards these treatments. Our results suggest the mechanism of AMB+LF synergy involves disruption to oxidative stress response, in addition to chelation of iron and zinc. Since Zap1 is conserved in C. neoformans and contains a putative drug binding domain, we suggest novel Zap1 binding molecules could be combined with existing antifungals to serve as synergistic antifungal treatments for this species.
Project description:Invasive fungal infections (IFIs) are difficult to treat. Few effective antifungal drugs are available and many have problems with toxicity, efficacy and drug-resistance. To overcome these challenges, existing therapies may be enhanced using more than one agent acting in synergy. Previously, we have found amphotericin B (AMB) and the iron chelator, lactoferrin (LF), were synergistic against Cryptococcus neoformans and Saccharomyces cerevisiae. This study investigates the mechanism of AMB+LF synergy using RNA-seq in Cryptococcus neoformans H99.
Project description:Transcriptome and network analyses in Saccharomyces cerevisiae reveal that amphotericin B and lactoferrin synergy disrupt metal homeostasis and stress response
Project description:The iron-binding glycoprotein lactoferrin exhibits anti-bacterial activity. To investigate the overall response of Bacillus cereus to lactoferrin, total transcriptome analyses were performed. Growth conditions were mMOD minimal medium, minimal medium plus 10 mg/ml lactoferrin, as well as minimal medium without iron source for comparison. Differential regulation of genes involved in iron acquisition as well as genes encoding enterotoxins and further virulence factors was of special interest.
Project description:Elucidation of molecular basis of Iron and zinc homeostasis is crucial to breed iron and zinc use efficient and iron -zinc biofortified maize cultivars. The present investigation was framed to decipher the global expression snapshot maize seedlings in response to iron and zinc starvtion. Genome-wide transcriptome assay was performed with ~18,000 transcripts distributed across the maize genome, in maize seedlings after exposing the seedlings to three Fe and Zn stress treatments (+Fe–Zn, –Fe+Zn, –Fe–Zn) along with control (+Fe+Zn). Microarrays were used to study the global gene expression pattern iron and zinc starvation responsive genes in maize.
Project description:In this study we used a transcriptomic approach to study the molecular determinants of the synergy between copper and fluconazole, in Candida glabrata, the second most frequent cause of invasive candidiasis. We demonstrate that copper acts together with fluconazole by downregulating three distinct pathways: azole efflux, ergosterol biosynthesis and zinc homeostasis. Coincidently, all these pathways are important for C. glabrata to cope with fluconazole stress. Therefore, when copper and fluconazole are combined cells fail to detoxify this drug and accumulate toxic methylated intermediates of sterol metabolism. This accumulation, possibly together with copper-induced lipid damages, should affect the activity of plasma membrane transporters, which impedes zinc uptake, leading to zinc depletion
Project description:Lactoferrin is a highly multifunctional protein. Indeed, it is involved in many physiological functions, including regulation of iron absorption and immune responses. We use microarrays to study the global genome expression of C. elegans fed with a nutraceutical product based on encapsulated lactoferrin.
Project description:Lactoferrin (LF) is an iron-binding multifunctional cationic glycoprotein secreted by exocrine glands and neutrophils in mammals. In this study, we created a mouse model of lipopolysaccharide (LPS)-induced acute lung injury and explored the anti-inflammatory effect and mechanism of bovine lactoferrin (bLF) in acute lung injury using the RNA sequencing (RNA-seq) technology and transcriptome analysis.
Project description:Amphotericin B (AMB) is the most widely used polyene antifungal drug for the treatment of systemic fungal infections including invasive aspergillosis. We aimed to understand molecular targets of AMB in Aspergillus fumigatus (Afu) by genomic approaches. Keywords: Aspergillus fumigatus treated with amphotericin B for 24 hours
