Farnesol: An approach on biofilms and nanotechnology

Farnesol prevents chlorpyrifos nephrotoxicity by modulating inflammatory mediators, Nrf2 and FXR and attenuating oxidative stress

Chlorpyrifos (CPF) is a broad-spectrum insecticide widely employed in agricultural field for pest control. Exposure to CPF is associated with serious effects to the main organs, including kidneys. Significant evidence denotes that oxidative stress (OS) and inflammation are implicated in CPF toxicity. This study aimed to evaluate the potential of farnesol (FAR) to modulate inflammatory mediators and farnesoid-X-receptor (FXR) and Nrf2 in a rat model of CPF nephrotoxicity. CPF and FAR were orally supplemented for 28 days and blood and kidney samples were collected for investigations. CPF administration elevated blood creatinine and urea, kidney MDA and NO, and upregulated NF-κB p65, IL-1β, TNF-α, iNOS, and caspase-3. In addition, CPF upregulated kidney Keap1, and decreased GSH, antioxidant enzymes, and Nrf2, FXR, HO-1 and NQO-1. FAR ameliorated creatinine and urea, prevented histopathological alterations, decreased MDA and NO, and enhanced antioxidants in CPF-administered rats. FAR modulated NF-κB p65, iNOS, TNF-α, IL-1β, caspase-3, Keap1, HO-1, NQO-1, Nrf2 and FXR. In silico investigations revealed the binding affinity of FAR towards Keap1 and FXR, as well as NF-κB, caspase-3, iNOS, and HO-1. In conclusion, FAR prevents CPF-induced kidney injury by attenuating OS, inflammation, and apoptosis, effects associated with modulation of FXR, Nrf2/HO-1 signaling and antioxidants.

Unlocking fungal quorum sensing: Oxylipins and yeast interactions enhance secondary metabolism in monascus

Exploring the symbiotic potential between fungal and yeast species, this study investigates the co-cultivation dynamics of Monascus, a prolific producer of pharmacologically relevant secondary metabolites, and Wickerhamomyce anomalous. The collaborative interaction between these microorganisms catalyzed a substantial elevation in the biosynthesis of secondary metabolites, prominently Monacolin K and natural pigments. Central to our discoveries was the identification and enhanced production of oxylipins (13S-hydroxyoctadecadienoic acid，13S-HODE), putative quorum-sensing molecules, within the co-culture environment. Augmentation with exogenous oxylipins not only boosted Monacolin K production by over half but also mirrored morphological adaptations in Monascus, affecting both spores and mycelial structures. This augmentation was paralleled by a significant upregulation in the transcriptional activity of genes integral to the Monacolin K biosynthetic pathway, as well as genes implicated in pigment and spore formation. Through elucidating the interconnected roles of quorum sensing, G-protein-coupled receptors, and the G-protein-mediate signaling pathway, this study provides a comprehensive view of the molecular underpinnings facilitating these metabolic enhancements. Collectively, our findings illuminate the profound influence of Wickerhamomyces anomalous co-culture on Monascus purpureus, advocating for oxylipins as a pivotal quorum-sensing mechanism driving the observed symbiotic benefits.

Transdermal administration of farnesol-ethosomes enhances the treatment of cutaneous candidiasis induced by Candida albicans in mice

Cutaneous candidiasis, caused by Candida albicans, is a severe and frustrating condition, and finding effective treatments can be challenging. Therefore, the development of farnesol-loaded nanoparticles is an exciting breakthrough. Ethosomes are a novel transdermal drug delivery carrier that incorporates a certain concentration (10-45%) of alcohols into lipid vesicles, resulting in improved permeability and encapsulation rates compared to conventional liposomes. Farnesol is a quorum-sensing molecule involved in morphogenesis regulation in C. albicans, and these ethosomes offer a promising new approach to treating this common fungal infection. This study develops the formulation of farnesol-loaded ethosomes (farnesol-ethosomes) and assesses applications in treating cutaneous candidiasis induced by C. albicans in vitro and in vivo. Farnesol-ethosomes were successfully developed by ethanol injection method. Therapeutic properties of farnesol-ethosomes, such as particle size, zeta potential, and morphology, were well characterized. According to the results, farnesol-ethosomes demonstrated an increased inhibition effect on cells' growth and biofilm formation in C. albicans. In Animal infection models, treating farnesol-ethosomes by transdermal administration effectively relieved symptoms caused by cutaneous candidiasis and reduced fungal burdens in quantity. We also observed that ethosomes significantly enhanced drug delivery efficacy in vitro and in vivo. These results indicate that farnesol-ethosomes can provide future promising roles in curing cutaneous candidiasis.

IMPORTANCE

Cutaneous candidiasis attributed to Candida infection is a prevalent condition that impacts individuals of all age groups. As a type of microbial community, biofilms confer benefits to host infections and mitigate the clinical effects of antifungal treatments. In C. albicans, the yeast-to-hypha transition and biofilm formation are effectively suppressed by farnesol through its modulation of multiple signaling pathway. However, the characteristics of farnesol such as hydrophobicity, volatility, degradability, and instability in various conditions can impose limitations on its effectiveness. Nanotechnology holds the potential to enhance the efficiency and utilization of this molecule. Treatment of farnesol-ethosomes by transdermal administration demonstrated a very remarkable therapeutic effect against C. albicans in infection model of cutaneous candidiasis in mice. Many patients suffering fungal skin infection will benefit from this study.

Comparative transcriptional analysis of Candida auris biofilms following farnesol and tyrosol treatment

Candida auris is frequently associated with biofilm-related invasive infections. The resistant profile of these biofilms necessitates innovative therapeutic options, where quorum sensing may be a potential target. Farnesol and tyrosol are two fungal quorum-sensing molecules with antifungal effects at supraphysiological concentrations. Here, we performed genome-wide transcript profiling with C. auris biofilms following farnesol or tyrosol exposure using transcriptome sequencing (RNA-Seq). Since transition metals play a central role in fungal virulence and biofilm formation, levels of intracellular calcium, magnesium, and iron were determined following farnesol or tyrosol treatment using inductively coupled plasma optical emission spectrometry. Farnesol caused an 89.9% and 73.8% significant reduction in the calcium and magnesium content, respectively, whereas tyrosol resulted in 82.6%, 76.6%, and 81.2% decrease in the calcium, magnesium, and iron content, respectively, compared to the control. Genes involved in biofilm events, glycolysis, ergosterol biosynthesis, fatty acid oxidation, iron metabolism, and autophagy were primarily affected in treated cells. To prove ergosterol quorum-sensing molecule interactions, microdilution-based susceptibility testing was performed, where the complexation of farnesol, but not tyrosol, with ergosterol was impeded in the presence of exogenous ergosterol, resulting in a minimum inhibitory concentration increase in the quorum-sensing molecules. This study revealed several farnesol- and tyrosol-specific responses, which will contribute to the development of alternative therapies against C. auris biofilms.

IMPORTANCE

Candida auris is a multidrug-resistant fungal pathogen, which is frequently associated with biofilm-related infections. Candida-derived quorum-sensing molecules (farnesol and tyrosol) play a pivotal role in the regulation of fungal morphogenesis and biofilm development. Furthermore, they may have remarkable anti-biofilm effects, especially at supraphysiological concentrations. Innovative therapeutic approaches interfering with quorum sensing may be a promising future strategy against C. auris biofilms; however, limited data are currently available concerning farnesol-induced and tyrosol-related molecular effects in C. auris. Here, we detected several genes involved in biofilm events, glycolysis, ergosterol biosynthesis, fatty acid oxidation, iron metabolism, and autophagy, which were primarily influenced following farnesol or tyrosol exposure. Moreover, calcium, magnesium, and iron homeostasis were also significantly affected. These results reveal those molecular and physiological events, which may support the development of novel therapeutic approaches against C. auris biofilms.

What is the role of microbial biotechnology and genetic engineering in medicine?

Microbial products are essential for developing various therapeutic agents, including antibiotics, anticancer drugs, vaccines, and therapeutic enzymes. Genetic engineering techniques, functional genomics, and synthetic biology unlock previously uncharacterized natural products. This review highlights major advances in microbial biotechnology, focusing on gene-based technologies for medical applications.

Chitosan nanoparticles encapsulating farnesol evaluated in vivo against Candida albicans

Farnesol is a natural essential oil with antimicrobial properties. Complexation of farnesol in chitosan nanoparticles can be useful to improve its bioavailability and potentiate its antifungal capabilities such as inhibition of hyphal and biofilm formation. The aim of this study was to develop and characterize chitosan nanoparticles with farnesol (NF) and evaluate their toxicity and antifungal action on C. albicans in vivo. The NF were prepared by the ionic gelation method and showed physicochemical characteristics such as diameter less than 200 nm, monodisperse distribution, positive zeta potential, spherical morphology, and stability after 120 days of storage. In the evaluation of toxicity in Galleria mellonella, NF did not reduce the survival rate, indicating that there was no toxicity in vivo at the doses tested. In the assays with G. mellonella infected by C. albicans, the larvae treated with NF had a high survival rate after 48 h, with a significant reduction of the fungal load and inhibition of the formation of biofilms and hyphae. In the murine model of vulvovaginal candidiasis (VVC), histopathological analysis showed a reduction in inflammatory parameters, fungal burden, and hyphal inhibition in mice treated with NF. The produced nanoparticles can be a promising alternative to inhibit C. albicans infection.

The regulatory functions of oxylipins in fungi: A review

Quorum sensing (QS) is a communication mechanism between microorganisms originally found in bacteria. In recent years, an important QS mechanism has been discovered in the field of fungi, namely, the lipoxygenase compound oxylipin of arachidonic acid acts as a QS molecule in life cycle control, particularly in the sexual and asexual development of fungi. However, the role of oxylipins in mediating eukaryotic communication has not been previously described. In this paper, we review the regulatory role of oxylipins and the underlying mechanisms and discuss the potential for application in major fungi. The role of oxylipin as a fungal quorum-sensing molecule is the main focus of the review. Besides, the quorum regulation of fungal morphological transformation, biofilm formation, virulence factors, secondary metabolism, infection, symbiosis, and other physiological behaviors are discussed. Moreover, future prospectives and applications are elaborated as well.

Total transcriptome analysis of Candida auris planktonic cells exposed to tyrosol

Tyrosol, a secondary metabolite of Candida species, regulates fungal morphogenesis, and its application may represent a novel innovative therapy against emerging multi-resistant fungal superbug such as Candida auris. In the current study, the effects of tyrosol on growth, redox homeostasis, intracellular microelement contents and activities of virulence-related enzymes released by C. auris were examined. To gain further information about the effect of tyrosol exposure, we revealed gene transcriptional changes using total transcriptome sequencing (RNA-Seq). At a concentration of 15 mM, tyrosol significantly decrease the growth of fungal cells within 2 h of its addition (5.6 × 107±1.2 × 107 and 2.5 × 107±0.6 × 107 colony forming unit/mL for control and tyrosol-treated cells, respectively). Furthermore, it enhanced the release of reactive oxygen species as confirmed by a dichlorofluorescein (DCF) assay (7.3 ± 1.8 [nmol DCF (OD640)-1] versus 16.8 ± 3.9 [nmol DCF (OD640)-1]), which was coincided with elevated superoxide dismutase, catalase and glutathione peroxidase activities. Tyrosol exerted in a 37%, 25%, 34% and 55% decrease in intracellular manganese, iron, zinc and copper contents, respectively, compared to control cells. The tyrosol treatment led to a 142 and 108 differentially transcripted genes with at least a 1.5-fold increase or decrease in transcription, respectively. Genes related to iron and fatty acid metabolism as well as nucleic acid synthesis were down-regulated, whereas those related to the antioxidative defence, adhesion and oxoacid metabolic processes were up-regulated. This study shows that tyrosol significantly influences growth, intracellular physiological processes and gene transcription in C. auris, which could highly support the development of novel treatment approaches against this important pathogen.

Fungal quorum-sensing molecules and antiseptics: a promising strategy for biofilm modulation?

New strategies to control fungal biofilms are essential, especially those that interfere in the biofilm organization process and cellular communication, known as quorum sensing. The effect of antiseptics and quorum-sensing molecules (QSMs) have been considered with regard to this; however, little has been elucidated, particularly because studies are often restricted to the action of antiseptics and QSMs against a few fungal genera. In this review, we discuss progress reported in the literature thus far and analyze, through in silico methods, 13 fungal QSMs with regard to their physicochemical, pharmacological, and toxicity properties, including their mutagenicity, tumorigenicity, hepatotoxicity, and nephrotoxicity. From these in silico analyses, we highlight 4-hydroxyphenylacetic acid and tryptophol as having satisfactory properties and, thus, propose that these should be investigated further as antifungal agents. We also recommend future in vitro approaches to determine the association of QSMs with commonly used antiseptics as potential antibiofilm agents.

Combination of Farnesol with Common Antifungal Drugs: Inhibitory Effect against Candida Species Isolated from Women with RVVC

Background and Objectives: Vulvovaginal candidiasis (VVC) is a mucous membrane infection, with an increased rate of antifungal resistance of Candida species. In this study, the in vitro efficacy of farnesol alone or in combination with traditional antifungals was assessed against resistant Candida strains recovered from women with VVC. Materials and Methods: Eighty Candida isolates were identified by multiplex polymerase chain reaction (PCR), and the antifungal susceptibility to amphotericin B (AMB), fluconazole (FLU), itraconazole (ITZ), voriconazole (VOR), clotrimazole (CTZ), and farnesol was tested by the standard microdilution method. The combinations of farnesol with each antifungal were calculated based on the fractional inhibitory concentration index (FICI). Result: Candida glabrata was the predominant species (48.75%) isolated from vaginal discharges, followed by C. albicans (43.75%), C. parapsilosis (3.75%), a mixed infection of C. albicans and C. glabrata (2.5%) and C. albicans and C. parapsilosis (1%). C. albicans and C. glabrata isolates had lower susceptibility to FLU (31.4% and 23.0%, respectively) and CTZ (37.1% and 33.3%, respectively). Importantly, there was "synergism" between farnesol-FLU and farnesol-ITZ against C. albicans and C. parapsilosis (FICI = 0.5 and 0.35, respectively), reverting the original azole-resistant profile. Conclusion: These findings indicate that farnesol can revert the resistance profile of azole by enhancing the activity of FLU and ITZ in resistant Candida isolates, which is a clinically promising result.

Nanoparticle-Based Photodynamic Inhibition of Candida albicans Biofilms with Interfering Quorum Sensing

Biofilm formation is a critical event in the pathogenesis and virulence of fungal infections caused by Candida albicans, giving rise to about a 1000-fold increase in the resistance to antifungal agents. Although photodynamic treatment (PDT) has been excellently implicated in bacterial infections, studies on its potential against fungal infection through the clearance of fungal biofilm formation remain at its infancy stage. Here, we have designed photodynamic nanoparticles with different sizes, modifications, and the ability of generating reactive oxygen species (ROS) to examine their effects on inhibiting biofilm formation and destructing mature biofilms of C. albicans. We found that the nanoparticles modified with oligo-chitosan exhibited a better binding efficiency for planktonic cells, leading to stronger inhibitory efficacy of the filamentation and the early-stage biofilm formation. However, for mature biofilms, the nanoparticles with the smallest size (∼15 nm) showed the fastest penetration speed and a pronounced destructing effect albeit conferring the lowest ROS-producing capability. The inhibitory effect of photodynamic nanoparticles was dependent on the disruption of fungal quorum sensing (QS) by the upregulation of QS molecules, farnesol and tyrosol, mediated through the upregulation of ARO 8 and DPP 3 expression. Our findings provide a powerful strategy of nanoparticulate PDT to combat fungal infections through the inhibition of both hyphal and biofilm formation by disrupting QS.

Natural products from traditional medicine as promising agents targeting at different stages of oral biofilm development

Oral cavity is an ideal habitat for more than 1,000 species of microorganisms. The diverse oral microbes form biofilms over the hard and soft tissues in the oral cavity, affecting the oral ecological balance and the development of oral diseases, such as caries, apical periodontitis, and periodontitis. Currently, antibiotics are the primary agents against infectious diseases; however, the emergence of drug resistance and the disruption of oral microecology have challenged their applications. The discovery of new antibiotic-independent agents is a promising strategy against biofilm-induced infections. Natural products from traditional medicine have shown potential antibiofilm activities in the oral cavity with high safety, cost-effectiveness, and minimal adverse drug reactions. Aiming to highlight the importance and functions of natural products from traditional medicine against oral biofilms, here we summarized and discussed the antibiofilm effects of natural products targeting at different stages of the biofilm formation process, including adhesion, proliferation, maturation, and dispersion, and their effects on multi-species biofilms. The perspective of antibiofilm agents for oral infectious diseases to restore the balance of oral microecology is also discussed.

Surface modification of poly(methyl-methacrylate) with farnesol to prevent Candida biofilm formation

Candida albicans promotes biofilm formation on dentures, which compromises the use of poly(methyl-methacrylate) (PMMA) as a dental material. Farnesol (FAR), a natural compound that prevents C. albicans filamentation and biofilm formation, was incorporated into the PMMA matrix, to obtain antifungal PMMA_FAR materials. The tested concentrations (0·0125% and 0·4%) of FAR, 24 h after incubation on YPD agar, inhibited filamentation of C. albicans. PMMA was modified with different FAR concentrations (3-12%), and physicochemical properties, antifungal activity and cytotoxicity of these modified materials (PMMA_FAR) were tested. The presence of FAR in PMMA_FAR composites was verified by Fourier-transform infrared spectroscopy (FT-IR). Incorporation of FAR into the polymeric matrix significantly decreased hydrophilicity at all tested concentrations and significantly reduced biofilm and planktonic cells metabolic activity in the early stage of biofilm formation at ≥6% FAR in PMMA. PMMA_FAR composites with <9% FAR were non-toxic. Modification of PMMA with FAR is a good strategy for reducing C. albicans biofilm formation on dentures.

Enhancing Colistin Activity against Colistin-Resistant Escherichia coli through Combination with Alginate Nanoparticles and Small Molecules

Bacterial resistance to antibiotics has become a major public health problem worldwide, with the yearly number of deaths exceeding 700,000. To face this well-acknowledged threat, new molecules and therapeutic methods are considered. In this context, the application of nanotechnology to fight bacterial infection represents a viable approach and has experienced tremendous developments in the last decades. Escherichia coli (E. coli) is responsible for severe diarrhea, notably in the breeding sector, and especially in pig farming. The resulting infection (named colibacillosis) occurs in young piglets and could lead to important economic losses. Here, we report the design of several new formulations based on colistin loaded on alginate nanoparticles (Alg NPs) in the absence, but also in the presence, of small molecules, such as components of essential oils, polyamines, and lactic acid. These new formulations, which are made by concomitantly binding colistin and small molecules to Alg NPs, were successfully tested against E. coli 184, a strain resistant to colistin. When colistin was associated with Alg NPs, the minimal inhibition concentration (MIC) decreased from 8 to 1 µg/mL. It is notable that when menthol or lactic acid was co-loaded with colistin on Alg NPs, the MIC of colistin drastically decreased, reaching 0.31 or 0.62 µg/mL, respectively. These novel bactericidal formulations, whose innocuity towards eukaryotic HT-29 cells was established in vitro, are presumed to permeabilize the bacterial membrane and provoke the leakage of intracellular proteins. Our findings revealed the potentiating effect of the Alg NPs on colistin, but also of the small molecules mentioned above. Such ecological and economical formulations are easy to produce and could be proposed, after confirmation by in vivo and toxicology tests, as therapeutic strategies to replace fading antibiotics.

Metabolic profile of Candida albicans and Candida parapsilosis interactions within dual-species biofilms

Within the oral cavity, the ability of Candida species to adhere and form biofilms is well recognized, especially when C. albicans is considered. Lately, a knowledge gap has been identified regarding dual-species communication of Candida isolates, as a way to increase virulence, with evidences being collected to support the existence of interactions between C. albicans and C. parapsilosis. The present work evaluated the synergistic effect of the two Candida species, and explored chemical interactions between cells, evaluating secreted extracellular alcohols and their relation with yeasts´ growth and matrix composition. Four clinical strains of C. albicans and C. parapsilosis species, isolated from single infections of different patients or from co-infections of a same patient, were tested. It was found that dual-species biofilms negatively impacted the growth of C. parapsilosis and their biofilm matrix, in comparison with mono-species biofilms, and had minor effects on the biofilm biomass. Alcohol secretion revealed to be species- and strain-dependent. However, some dual-species cultures produced much higher amounts of some alcohols (E-nerolidol and E, E-Farnesol) than the respective single cultures, which proves the existence of a synergy between species. These results show evidence that interactions between Candida species affect the biofilm matrix, which is a key element of oral biofilms.