The fungal Quorum-Sensing-Molecule Farnesol activates Innate Immune Cells but suppresses Cellular Adaptive Immunity
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ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Michael Weber
PROVIDER: E-MTAB-2813 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:UnlabelledFarnesol, produced by the polymorphic fungus Candida albicans, is the first quorum-sensing molecule discovered in eukaryotes. Its main function is control of C. albicans filamentation, a process closely linked to pathogenesis. In this study, we analyzed the effects of farnesol on innate immune cells known to be important for fungal clearance and protective immunity. Farnesol enhanced the expression of activation markers on monocytes (CD86 and HLA-DR) and neutrophils (CD66b and CD11b) and promoted oxidative burst and the release of proinflammatory cytokines (tumor necrosis factor alpha [TNF-?] and macrophage inflammatory protein 1 alpha [MIP-1?]). However, this activation did not result in enhanced fungal uptake or killing. Furthermore, the differentiation of monocytes to immature dendritic cells (iDC) was significantly affected by farnesol. Several markers important for maturation and antigen presentation like CD1a, CD83, CD86, and CD80 were significantly reduced in the presence of farnesol. Furthermore, farnesol modulated migrational behavior and cytokine release and impaired the ability of DC to induce T cell proliferation. Of major importance was the absence of interleukin 12 (IL-12) induction in iDC generated in the presence of farnesol. Transcriptome analyses revealed a farnesol-induced shift in effector molecule expression and a down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor during monocytes to iDC differentiation. Taken together, our data unveil the ability of farnesol to act as a virulence factor of C. albicans by influencing innate immune cells to promote inflammation and mitigating the Th1 response, which is essential for fungal clearance.ImportanceFarnesol is a quorum-sensing molecule which controls morphological plasticity of the pathogenic yeast Candida albicans. As such, it is a major mediator of intraspecies communication. Here, we investigated the impact of farnesol on human innate immune cells known to be important for fungal clearance and protective immunity. We show that farnesol is able to enhance inflammation by inducing activation of neutrophils and monocytes. At the same time, farnesol impairs differentiation of monocytes into immature dendritic cells (iDC) by modulating surface phenotype, cytokine release and migrational behavior. Consequently, iDC generated in the presence of farnesol are unable to induce proper T cell responses and fail to secrete Th1 promoting interleukin 12 (IL-12). As farnesol induced down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor, desensitization to GM-CSF could potentially explain transcriptional reprofiling of iDC effector molecules. Taken together, our data show that farnesol can also mediate Candida-host communication and is able to act as a virulence factor.
| S-EPMC4453522 | biostudies-literature
Project description:In microbial biofilms, microorganisms utilize secreted signaling chemical molecules to coordinate their collective behavior. Farnesol is a quorum sensing molecule secreted by the fungal species Candida albicans and shown to play a central physiological role during fungal biofilm growth. Our pervious in vitro and in vivo studies characterized an intricate interaction between C. albicans and the bacterial pathogen Staphylococcus aureus, as these species coexist in biofilm. In this study, we aimed to investigate the impact of farnesol on S. aureus survival, biofilm formation, and response to antimicrobials. The results demonstrated that in the presence of exogenously supplemented farnesol or farnesol secreted by C. albicans in biofilm, S. aureus exhibited significantly enhanced tolerance to antimicrobials. By using gene expression studies, S. aureus mutant strains, and chemical inhibitors, the mechanism for the enhanced tolerance was attributed to upregulation of drug efflux pumps. Importantly, we showed that sequential exposure of S. aureus to farnesol generated a phenotype of high resistance to antimicrobials. Based on the presence of intracellular reactive oxygen species upon farnesol exposure, we hypothesize that antimicrobial tolerance in S. aureus may be mediated by farnesol-induced oxidative stress triggering the upregulation of efflux pumps, as part of a general stress response system. Hence, in mixed biofilms, C. albicans may influence the pathogenicity of S. aureus through acquisition of a drug-tolerant phenotype, with important therapeutic implications. Understanding interspecies signaling in polymicrobial biofilms and the specific drug resistance responses to secreted molecules may lead to the identification of novel targets for drug development.
| S-EPMC5700358 | biostudies-literature
Project description:Microbial species utilize secreted-signaling molecules to coordinate their behavior. Our previous investigations demonstrated a key role for the Candida albicans-secreted quorum-sensing molecule farnesol in modulating Staphylococcus aureus response to antimicrobials in mixed biofilms. In this study, we aimed to provide mechanistic insights into the impact of farnesol on S. aureus within the context of inter-species interactions. To mimic biofilm dynamics, farnesol-sensitized S. aureus cells were generated via sequential farnesol exposure. The sensitized phenotype exhibited dramatic loss of the typical pigment, which we identified as staphyloxanthin, an important virulence factor synthesized by the Crt operon in S. aureus. Additionally, farnesol exposure exerted oxidative-stress as indicated by transcriptional analysis demonstrating alterations in redox-sensors and major virulence regulators. Paradoxically, the activated stress-response conferred S. aureus with enhanced tolerance to H2O2 and phagocytic killing. Since expression of enzymes in the staphyloxanthin biosynthesis pathway was not impacted by farnesol, we generated a theoretical-binding model which indicated that farnesol may block staphyloxanthin biosynthesis via competitive-binding to the CrtM enzyme crucial for staphyloxanthin synthesis, due to high structural similarity to the CrtM substrate. Finally, mixed growth with C. albicans was found to similarly induce S. aureus depigmentation, but not during growth with a farnesol-deficient C. albicans strain. Collectively, the findings demonstrate that a fungal molecule acts as a redox-cycler eliciting a bacterial stress response via activation of the thiol-based redox system under the control of global regulators. Therefore, farnesol-induced transcriptional modulations of key regulatory networks in S. aureus may modulate the pathogenesis of C. albicans-S. aureus co-infections.
| S-EPMC6629188 | biostudies-literature
Project description:The natural bioactive molecule farnesol (FAR) is widely studied mainly for its antibiofilm and antimicrobial properties. In addition, it increases the effectiveness of some antimicrobial substances, which makes it interesting for the development of combined therapy. In the present work, the effect of FAR either alone or in combination with oxacillin (OXA) on mixed biofilms formed by clinically relevant pathogens, Candida albicans and Staphylococcus aureus, was studied. S. aureus isolates used for biofilm formation originated from blood cultures and central venous catheters (CVC) were characterized in terms of antimicrobial resistance. The minimal biofilm inhibitory concentration (MBIC50) for FAR of 48 h mixed biofilms formed by the C. albicans and methicillin-sensitive S. aureus (MSSA) was determined to be 125 μM, and for the mixed biofilms with methicillin-resistant S. aureus (MRSA) was determined to be 250 μM. Treatment of mixed biofilms with OXA (2 mg/mL) showed ≤4% inhibition; however, the combination of OXA (2 mg/mL) and FAR (300 μM) resulted in 80% inhibition of biofilms. In addition, planktonic cells of S. aureus exhibited an increased susceptibility to OXA, cefoxitin and kanamycin in the presence of FAR (150 and 300 μM). Scanning electron microscopy (SEM) micrographs confirmed patchy biofilm and lack of candidal hyphae in the samples treated with FAR and FAR/OXA in comparison to control and mixed biofilms treated only with OXA. Intriguingly, in a pilot experiment using fluorescence in situ hybridization (FISH), considerable differences in activity (as indicated by ribosome content) of staphylococcal cells were detected. While the activity rate of the staphylococci in mixed biofilms treated with FAR was high, no FISH-positive signal for staphylococcal cells was found in the biofilm treated with FAR/OXA.
| S-EPMC10044556 | biostudies-literature
Project description:Gene expression profiles of Molt4 cells treated with DMCS (vehicle) or farnesol were compared to understand the mechanism by which farnesol induces apoptosis in these cells.
2014-05-01 | GSE46670 | GEO
Project description:The antifungal resistance threat posed by Candida auris necessitates bold and innovative therapeutic options. Farnesol, a quorum-sensing molecule with a potential antifungal and/or adjuvant effect; it may be a promising candidate in alternative treatment regimens. To gain further insights into the farnesol-related effect on C. auris, genome-wide gene expression analysis was performed using RNA-Seq. Farnesol exposure resulted in 1,766 differentially expressed genes. Of these, 447 and 304 genes with at least 1.5-fold increase or decrease in expression, respectively, were selected for further investigation. Genes involved in morphogenesis, biofilm events (maturation and dispersion), gluconeogenesis, iron metabolism, and regulation of RNA biosynthesis showed down-regulation, whereas those related to antioxidative defense, transmembrane transport, glyoxylate cycle, fatty acid β-oxidation, and peroxisome processes were up-regulated. In addition, farnesol treatment increased the expression of certain efflux pump genes, including MDR1, CDR1, and CDR2. Growth, measured by change in CFU number, was significantly inhibited within 2 hours of the addition of farnesol (5.8×10^7±1.1×10^7 and 1.1×10^7±0.3×10^7 CFU/ml for untreated control and farnesol-exposed cells, respectively) (p<0.001). In addition, farnesol treatment caused a significant reduction in intracellular iron (152.2±21.1 vs. 116.0±10.0 mg/kg), manganese (67.9±5.1 vs. 18.6±1.8 mg/kg), and zinc (787.8±22.2 vs. 245.8±34.4 mg/kg) (p<0.05–0.001) compared to untreated control cells, whereas the level of cooper was significantly increased (274.6±15.7 vs. 828.8±106.4 mg/kg) (p<0.001). Our data demonstrate that farnesol significantly influences the growth, intracellular metal ion contents, and gene expression related to fatty acid metabolism, which could open new directions in developing alternative therapies against C. auris.
2021-09-30 | GSE180093 | GEO
Project description:We used the results of a genome sequence survey to design and manufacture partial genomic microarrays that were applied to determining the transcriptional response of C. parapsilosis to the presence of exogenous farnesol. Keywords: drug response, farnesol, Transcriptional profiling was performed following exposure to 50 microM of farnesol compare to the control experiment (no treatment). Six independent experiment comparisons (including 3 dye swaps) were performed.
2010-06-11 | E-GEOD-6318 | biostudies-arrayexpress
Project description:We used the results of a genome sequence survey to design and manufacture partial genomic microarrays that were applied to determining the transcriptional response of C. parapsilosis to the presence of exogenous farnesol. Keywords: drug response, farnesol,
2007-03-01 | GSE6318 | GEO
Project description:Bacteria commonly exist in high cell density populations, making them prone to viral predation and horizontal gene transfer (HGT) through transformation and conjugation. To combat these invaders, bacteria possess an arsenal of defenses, such as CRISPR-Cas adaptive immunity. Many bacterial populations coordinate their behavior as cell density increases, using quorum sensing (QS) signaling. In this study, we demonstrate that QS regulation results in increased expression of the type I-E, I-F, and III-A CRISPR-Cas systems in Serratia cells in high-density populations. Strains unable to communicate via QS were less effective at defending against invaders targeted by any of the three CRISPR-Cas systems. Additionally, the acquisition of immunity by the type I-E and I-F systems was impaired in the absence of QS signaling. We propose that bacteria can use chemical communication to modulate the balance between community-level defense requirements in high cell density populations and host fitness costs of basal CRISPR-Cas activity.
| S-EPMC5179492 | biostudies-literature
Project description:Gene expression profiles of Molt4 cells treated with DMCS (vehicle) or farnesol were compared to understand the mechanism by which farnesol induces apoptosis in these cells. Molt4 cells were treated with 75 uM farnesol for 4 hrs to compare with vehicle-treated Molt4 cells. RNA from three replicates for each treatment was then isolated for microarray analysis.
2014-05-01 | E-GEOD-46670 | biostudies-arrayexpress