Candida albicans ?-Glucan-Containing Particles Increase HO-1 Expression in Oral Keratinocytes via a Reactive Oxygen Species/p38 Mitogen-Activated Protein Kinase/Nrf2 Pathway.
ABSTRACT: Oral keratinocytes provide the first line of host defense against oral candidiasis. We speculated that interactions of fungal cell wall components with oral keratinocytes regulate the stress response against Candida infection and examined the expression of genes induced by heat-killed Candida albicans in oral immortalized keratinocytes using a cDNA microarray technique. Of 24,000 genes revealed by that analysis, we focused on HO-1, a stress-inducible gene, as its expression was increased by both heat-killed and live C. albicans In histological findings, HO-1 expression in the superficial layers of the oral epithelium following Candida infection was elevated compared to that in healthy epithelium. We then investigated fungal cell wall components involved in induction of HO-1 expression and found that ?-glucan-containing particles (?-GPs) increased its expression. Furthermore, ?-glucan was observed on the surface of both heat-killed C. albicans and Candida cells that had invaded the oral epithelium. Fungal ?-GPs also promoted induction of intracellular reactive oxygen species (ROS), NADPH oxidase activation, and p38 mitogen-activated protein kinase (MAPK) phosphorylation, while those specific inhibitors inhibited the HO-1 expression induced by fungal ?-GPs. Moreover, fungal ?-GPs induced Nrf2 translocation into nuclei via p38 MAPK signaling, while the HO-1 expression induced by fungal ?-GPs was inhibited by Nrf2-specific small interfering RNA (siRNA). Finally, knockdown of cells by HO-1- and Nrf2-specific siRNAs resulted in increased ?-GP-mediated ROS production compared to that in the control cells. Our results show that the HO-1 induced by fungal ?-GPs via ROS/p38 MAPK/Nrf2 from oral keratinocytes may have important roles in host defense against the stress caused by Candida infection in the oral epithelium.
Project description:The effects of Candida albicans on the metastatic activity of oral squamous cell carcinoma was observed in vitro and in vivo. In the in vitro experimental setup HO-1-N-1 and HSC-2 human oral squamous cell carcinoma cell lines were treated with zymosan, heat-killed Candida albicans, heat-killed C. parapsilosis, live C. albicans and live C. parapsilosis. Whole transcriptomics was performed of the human tumor cells. In the in vivo experiment human HSC-2 tumor cells were injected to the tongue of mice. Whole transcriptomic analysis was performed of the human HSC-2 derived tumor cells comparing control tumor and oral candidiasis treated tumor. Overall design: in vitro: 2 OSCC cell lines untreated or treated with 5 different treatments. in vivo: 4 control tumors, 4 oral candidiasis-treated tumors.
Project description:Candida albicans infection can cause skin, vulvar, or oral pain. Despite the obvious algesic activity of C. albicans, the molecular mechanisms of fungal nociception remain largely unknown. Here we show that the C. albicans-specific signaling pathway led to severe mechanical allodynia. We discovered that C. albicans-derived ?-glucan stimulated nociceptors depending on Dectin-1, and two pathways in inflammatory pain. The major pathway operates via the Dectin-1-mediated ATP-P2X3/P2X2/3 axis through intercellular relationships between keratinocytes and primary sensory neurons, which depends on the ATP transporter vesicular nucleotide transporter (VNUT). The other pathway operates via the Dectin-1-mediated PLC-TRPV1/TRPA1 axis in primary sensory neurons. Intriguingly, C. albicans-derived ?-glucan has the ability to enhance histamine-independent pruritus, and VNUT inhibitor clodronate can be used to treat unpleasant feelings induced by ?-glucan. Collectively, this is the first report to indicate that Dectin-1 and VNUT mediated innate sensory mechanisms that detect fungal infection.
Project description:Candida albicans is the most common fungus in the human intestinal microbiota but not in mice. To make a murine sepsis model more closely resemble human sepsis and to explore the role of intestinal C. albicans, in the absence of candidemia, in bacterial sepsis, live- or heat-killed C. albicans was orally administered to mice at 3h prior to cecal ligation and puncture (CLP). A higher mortality rate of CLP was demonstrated with Candida-administration (live- or heat-killed) prior to CLP. Fecal Candida presented only in experiments with live-Candida administration. Despite the absence of candidemia, serum (1?3)-?-D-glucan (BG) was higher in CLP with Candida-administration than CLP-controls (normal saline administration) at 6h and/or 18h post-CLP. Interestingly, fluconazole attenuated the fecal Candida burden and improved survival in mice with live-Candida administration, but not CLP-control. Microbiota analysis revealed increased Bacteroides spp. and reduced Lactobacillus spp. in feces after Candida administration. Additionally, synergy in the elicitation of cytokine production from bone marrow-derived macrophages, in vitro, was demonstrated by co-exposure to heat-killed E. coli and BG. In conclusion, intestinal abundance of fungi and/or fungal-molecules was associated with increased bacterial sepsis-severity, perhaps through enhanced cytokine elicitation induced by synergistic responses to molecules from gut-derived bacteria and fungi. Conversely, reducing intestinal fungal burdens decreased serum BG and attenuated sepsis in our model.
Project description:During oropharyngeal candidiasis (OPC), Candida albicans proliferates and invades the superficial oral epithelium. Ephrin type-A receptor 2 (EphA2) functions as an oral epithelial cell ?-glucan receptor that triggers the production of proinflammatory mediators in response to fungal infection. Because EphA2 is also expressed by neutrophils, we investigated its role in neutrophil candidacidal activity during OPC. We found that EphA2 on stromal cells is required for the accumulation of phagocytes in the oral mucosa of mice with OPC. EphA2 on neutrophils is also central to host defense against OPC. The interaction of neutrophil EphA2 with serum-opsonized C. albicans yeast activates the MEK-ERK signaling pathway, leading to NADPH subunit p47phox site-specific phospho-priming. This priming increases intracellular reactive oxygen species production and enhances fungal killing. Thus, in neutrophils, EphA2 serves as a receptor for ?-glucans that augments Fc? receptor-mediated antifungal activity and controls early fungal proliferation during OPC.
Project description:This SuperSeries is composed of the following subset Series: GSE13318: Expression profiling of Candida albicans and Candida dubliniensis in reconstituted human oral epithelium 30 min p.i. GSE13345: Expression profiling of Candida albicans and Candida dubliniensis in reconstituted human oral epithelium 90 min p.i. GSE13352: Comparative expression profiling in Candida albicans and Candida dubliniensis in inocula, RHE, and PCF cultures Refer to individual Series
Project description:In this study we have analysed the regulation of miRNA in bone marrow derived macrophages in response to the fungal pathogen heat killed Candida albicans and bacterial cell wall component, LPS. The aim of the study was to identify and validate miRNAs involved in the innate immune system in response to fungal and bacterial stimuli and investigate potential mechanisms for their transcription. Overall design: Three mice were used as 3 biological replicates. The bone marow derived macrophages from each mouse were divided into two and either left untreated or were stimulatred for 16 h with heat killed Candida albicans.
Project description:Oral candidiasis (OC) caused by the fungal pathogen Candida albicans is the most common opportunistic infection in immunocompromised populations. The dramatic increase in resistance to common antifungal agents has emphasized the importance of identifying alternative therapeutic options. Antimicrobial peptides have emerged as promising drug candidates due to their antimicrobial properties; specifically, histatin-5 (Hst-5), a peptide naturally produced and secreted by human salivary glands, has demonstrated potent activity against C. albicans However, as we previously demonstrated vulnerability for Hst-5 to proteolysis by C. albicans proteolytic enzymes at specific amino acid residues, a new variant (K11R-K17R) was designed with amino acid substitutions at the identified cleavage sites. The new resistant peptide demonstrated no cytotoxicity to erythrocytes or human oral keratinocytes. To evaluate the potential of the new peptide for clinical application, we utilized our FDA-approved polymer-based bioadhesive hydrogel as a delivery system and developed a therapeutic formulation specifically designed for oral topical application. The new formulation was demonstrated to be effective against C. albicans strains resistant to the traditional antifungals, and the in vitro therapeutic efficacy was found to be comparable to that of the common topical antifungal agents in clinical use. Importantly, in addition to its antifungal properties, our findings also demonstrated that the new peptide variant induces cell proliferation and rapid cell migration of human oral keratinocytes, indicative of wound healing properties. The findings from this study support the progression of the novel formulation as a therapeutic agent against oral candidiasis, as well as a therapeutic modality for promoting wound healing.
Project description:Candida albicans is the most common human fungal pathogen causing mucosal and systemic infections, but human anti-fungal immunity remains poorly defined. Expression profiling of Candida-stimulated human peripheral blood mononuclear cells (PBMCs) provides new insights into Candida-specific host defense mechanisms in humans. Total RNA was extracted from PBMCs from healthy human volunteers. PBMCs were stimulated with heat-killed Candida albicans (10^6/ml), non-fungal inflammatory stimuli or RPMI control for 4 or 24 hours. A large number of biological replicates (>20) were included per stimulation condition and duration.
Project description:Oral microbiota contribute to health and disease, and their disruption may influence the course of oral diseases. Here, we used pyrosequencing to characterize the oral bacteriome and mycobiome of 12 HIV-infected patients and matched 12 uninfected controls. The number of bacterial and fungal genera in individuals ranged between 8-14 and 1-9, among uninfected and HIV-infected participants, respectively. The core oral bacteriome (COB) comprised 14 genera, of which 13 were common between the two groups. In contrast, the core oral mycobiome (COM) differed between HIV-infected and uninfected individuals, with Candida being the predominant fungus in both groups. Among Candida species, C. albicans was the most common (58% in uninfected and 83% in HIV-infected participants). Furthermore, 15 and 12 bacteria-fungi pairs were correlated significantly within uninfected and HIV-infected groups, respectively. Increase in Candida colonization was associated with a concomitant decrease in the abundance of Pichia, suggesting antagonism. We found that Pichia spent medium (PSM) inhibited growth of Candida, Aspergillus and Fusarium. Moreover, Pichia cells and PSM inhibited Candida biofilms (P?=?.002 and .02, respectively, compared to untreated controls). The mechanism by which Pichia inhibited Candida involved nutrient limitation, and modulation of growth and virulence factors. Finally, in an experimental murine model of oral candidiasis, we demonstrated that mice treated with PSM exhibited significantly lower infection score (P?=?.011) and fungal burden (P?=?.04) compared to untreated mice. Moreover, tongues of PSM-treated mice had few hyphae and intact epithelium, while vehicle- and nystatin-treated mice exhibited extensive fungal invasion of tissue with epithelial disruption. These results showed that PSM was efficacious against oral candidiasis in vitro and in vivo. The inhibitory activity of PSM was associated with secretory protein/s. Our findings provide the first evidence of interaction among members of the oral mycobiota, and identifies a potential novel antifungal.
Project description:Oral candidiasis is closely associated with changes in oral fungal biodiversity and is caused primarily by Candida albicans. However, the widespread use of empiric and prophylactic antifungal drugs has caused a shift in fungal biodiversity towards other Candida or yeast species. Recently, next-generation sequencing (NGS) has provided an improvement over conventional culture techniques, allowing rapid comprehensive analysis of oral fungal biodiversity. In this study, we used NGS to examine the oral fungal biodiversity of 27 patients with pseudomembranous oral candidiasis (POC) and 66 healthy controls. The total number of fungal species in patients with POC and healthy controls was 67 and 86, respectively. The copy number of total PCR products and the proportion of non-C. albicans, especially C. dubliniensis, in patients with POC, were higher than those in healthy controls. The detection patterns in patients with POC were similar to those in controls after antifungal treatment. Interestingly, the number of fungal species and the copy number of total PCR products in healthy controls increased with aging. These results suggest that high fungal biodiversity and aging might be involved in the pathogenesis of oral candidiasis. We therefore conclude that NGS is a useful technique for investigating oral candida infections.