Albicans Infection Research Articles

Mechanism of human airway epithelial cell injury induced by Candida albicans infection

Objective: To investigate the immune mechanism of human airway epithelial cell injury induced by invasion of Candida albicans with different biofilm formation abilities. Methods: Twenty-five strains of Candida albicans isolated and cultured in General Hospital of Ningxia Medical University from June to December 2019 were selected, and quality control strain SC5314 was used as the standard strain. An in vitro model of Candida albicans biofilm was established, and the biofilm formation ability of different Candida albicans was detected by crystal violet staining and enzyme plate method. The absorbance value at 570 nm (A570) was determined by enzyme plate method. A570≥0.5, 0.25<A570<0.5 and A570≤0.25 indicated strong biofilm Candida albicans form (SBF), moderate biofilm Candida albicans form (DRF) and weak biofilm Candida albicans form (WBF), respectively. The gas-liquid phase culture model of human airway epithelial cells was isolated and established in vitro and divided into five groups, including blank control group (n=20), standard strain group (n=20), strong biofilm group (n=19), weak biofilm group (n=17) and fluconazole-resistant group (n=18).The morphology of the epithelial cells was observed by scanning electron microscope (SEM), and the expression of marker protein in the model was detected by immunofluorescence in vitro. The level of lactate dehydrogenase (LDH) in cells was detected by microplate method, and the secretion of β-defensin (hBD2), granulocyte macrophage colony stimulating factor(GM-CSF) and granulocyte colony-stimulating factor (G-CSF) was detected by enzyme-linked immunosorbent assay (ELISA). Results: The strong biofilm strains grew with interlacing mycelia, and very few yeast cells could be seen wrapped in them.SEM observed that the mycelia of epithelial cells in gas-liquid phase culture could actively invade epithelial cells, and the expression of acetylated tubulin and keratin in cilia were significantly reduced, while the expression of Ki67 was down-regulated.The LDH levels in the blank control group, standard strain group, strong biofilm group, weak biofilm group, and fluconazole-resistant group were (12.21±5.68), (46.35±6.35), (18.69±4.38), (12.56±3.69), and (13.48±4.28) U/L, respectively, with statistically significant differences (P<0.001). Compared with standard strain group, LDH level in strong biofilm group, weak biofilm group and fluconazole resistant group were significantly decreased (all P<0.01). The hBD2 levels of the five groups were (26.14±0.77), (56.18±0.83), (30.66±2.59), (29.22±0.48), (28.28±1.56) ng/L, respectively, with statistically significant differences(P<0.001). Compared with the blank control group, SC5314-treated epithelial cells induced an increase of intracellular hBD2 expression (P<0.001). The differences in the expression of GM-CSF and G-CSF between different groups were not statistically significant(all P>0.05). Conclusion: Strong biofilm Candida albican can inhibit cell proliferation, disrupt the integrity of epithelial cells and induce cell damage by down-regulating the expression of cell proliferation-related protein.

Investigation of the location and secretion features of Candida albicans enolase with monoclonal antibodies

PurposeThe glycolytic enzyme enolase plays important role in the pathogenesis of Candida albicans infection and has been also considered as a promising molecular marker for the diagnosis of invasive candidiasis. This study aimed to investigate the location and secretion features of Candida albicans enolase (CaEno) with a couple of specific monoclonal antibodies (mAbs).MethodsTwo mAbs named 9H8 and 10H8 against CaEno were generated by fusing SP2/0 myeloma cell with the spleen lymphocytes from CaEno immunized mice. The specificity of the mAbs was then validated by Western blot and liquid chromatography-mass spectrometry (LC–MS/MS). A diverse set of experiments were conducted based on the pair of mAbs which involved immunohistochemical staining analysis, whole cell enzyme-linked immunosorbent assay (ELISA), double antibody sandwich ELISA, and confocal microscopy to analyze the possible location and secretion features of CaEno.ResultsCaEno is abundantly expressed in the cytoplasm of C. albicans blastospores and is distributed in a ring-shaped pattern along the cell wall. CaEno appeared in the hyphal C. albicans as just a “mushroom” form. CaEno was found to be weakly expressed on the surface of blastospores but constantly expressed at various stages of growth. CaEno concentrations in C. albicans blastospores culture supernatant are considerably higher than in C. albicans hyphae culture supernatant. The dynamic changes of supernatant CaEno concentration in blastospores and hyphal C. albicans exhibit distinct features, although both appear to be associated with the C. albicans growth state. When cultivated under normal circumstances, however, no apparent CaEno degradation was seen in the cell-free supernatant.ConclusionOur results implied that CaEno was constantly expressed on the cell surface and its secretion features varied according to the growth stage of C. albicans. However, further experimental and theoretical studies are needed in future to identify the specific mechanisms by which this phenomenon can arise.

Increased Virulence and Large-Scale Reduction in Genome Size of Tetraploid Candida albicans Evolved in Nematode Hosts.

Candida albicans is an opportunistic fungal pathogen of humans, yet the within-host dynamics of C. albicans infection are not clear. While C. albicans is commonly diploid, it exhibits a range of ploidies, including tetraploidy. Previous work found that tetraploid C. albicans populations exhibited rapid adaptation and significant genome instability when evolved in vitro. Host immune function alters the rate and magnitude of C. albicans virulence evolution, but the effects of the host immunity on tetraploid C. albicans populations are unclear. Here, we tested the effects of the host immunity on genome stability and virulence evolution of tetraploid C. albicans using experimental evolution. We selected for C. albicans increased virulence within either immunocompetent or immunocompromised Caenorhabditis elegans hosts. After nine passages we observed a response to selection for increased virulence. Both populations exposed to either immunocompetent or immunocompromised hosts increased virulence after passage through C. elegans hosts. However, the C. albicans populations passaged through immunocompetent hosts under selection exhibited unique temporal dynamics, a rapid increase in virulence and then subsequent loss of virulence. Most C. albicans populations exhibited genome size reduction within six passages, however populations exposed to immunocompetent hosts exhibited the most rapid transition to ~diploid. Therefore, we found that tetraploids rapidly increase in virulence and decrease genome size within host environments. Further, the combination of selection for greater virulence in the presence ofimmunocompetent hosts results in major virulence fluctuations and genome size changes. Thus, host immunity significantly impacts the evolutionary trajectories of tetraploid C. albicans.

Extrathymic expression of Aire controls the induction of effective TH17 cell-mediated immune response to Candida albicans.

Patients with loss of function in the gene encoding the master regulator of central tolerance AIRE suffer from a devastating disorder called autoimmune polyendocrine syndrome type 1 (APS-1), characterized by a spectrum of autoimmune diseases and severe mucocutaneous candidiasis. Although the key mechanisms underlying the development of autoimmunity in patients with APS-1 are well established, the underlying cause of the increased susceptibility to Candida albicans infection remains less understood. Here, we show that Aire+MHCII+ type 3 innate lymphoid cells (ILC3s) could sense, internalize and present C. albicans and had a critical role in the induction of Candida-specific T helper 17 (TH17) cell clones. Extrathymic Rorc-Cre-mediated deletion of Aire resulted in impaired generation of Candida-specific TH17 cells and subsequent overgrowth of C. albicans in the mucosal tissues. Collectively, our observations identify a previously unrecognized regulatory mechanism for effective defense responses against fungal infections.

Machine-learning-based virtual screening to repurpose drugs for treatment of Candida albicans infection.

Approximately 30% of Candida genus isolates are resistant to all currently available antifungal drugs and it is highly important to develop new treatments. Additionally, many current drugs are toxic and cause unwanted side effects. 1,3-beta-glucan synthase is an essential enzyme that builds the cell walls of Candida. Targeting CaFKS1, a subunit of the synthase, could be used to fight Candida. In the present study, a machine-learning model based on chemical descriptors was trained to recognise drugs that inhibit CaFKS1. The model attained 96.72% accuracy for classifying between active and inactive drug compounds. Descriptors for FDA-approved and other drugs were calculated, and the model was used to predict the potential activity of these drugs against CaFKS1. Several drugs, including goserelin and icatibant, were detected as active with high confidence. Many of the drugs, interestingly, were gonadotrophin-releasing hormone (GnRH) antagonists or agonists. A literature search found that five of the predicted drugs inhibit Candida experimentally. This study yields promising drugs to be repurposed to combat Candida albicans infection. Future steps include testing the drugs on fungal cells in vitro.

Repurposing vilanterol as a novel potential antifungal for Candida albicans: In-silico & in-vitro approach

Candida albicans infects immune-compromised persons, and its resistance to antifungal drugs has become a significant health concern, which causes a higher mortality rate worldwide. This study aims to find novel antifungals against Candida albicans using a computational drug repurposing approach targeting lanosterol 14-alpha demethylase and experimental testing of the drugs. We used the virtual docking method for initial drug screening. We did minimum inhibitory concentration (MIC), and disc diffusion assay for antifungal determination, and the fungicidal property was detected using the fluorescent microscopy method. Further, we carried out Erg11p drug interaction studies by molecular dynamics simulations and binding free energy analysis. Docking results identified bimatoprost and vilanterol as novel drug hits for C. albicans. In-vitro studies confirmed that vilanterol possesses an active antifungal activity (MIC- 500 µg/ml). The fluorescent microscopy study revealed that vilanterol disrupts the cell membrane of C. albicans at a tested concentration of 600 µg/ml. Molecular dynamics simulations and structural decomposition analysis confirmed the durability of the Erg11p-vilanterol complex's interaction. Our study concludes that vilanterol has a novel potential fungicidal activity against C. albicans. On the other hand, we hypothesize it may alter the ergosterol production by binding lanosterol 14α-demethylase. Previous clinical studies have proved that vilanterol oral doses of up to 500 μg were safe in humans. Our study shows that vilanterol may be a new drug class for treating C. albicans. Therefore, we report that vilanterol could be repurposed possibly against C. albicans infections.

Neutrophil Extracellular Traps in Candida albicans Infection.

Candida albicans is the most common pathogen causing clinical Candida infections. Neutrophils are a key member of the host innate immunity that plays an essential role in clearing invading C. albicans. In addition to the well-known defensive approaches such as phagocytosis, degranulation, and reactive oxygen species production, the formation of neutrophil extracellular traps (NETs) has also become an important way for neutrophils to defend against various pathogens. C. albicans has been reported to be capable of activating neutrophils to release NETs that subsequently kill fungi. The induction of NETs is affected by both the morphology and virulence factors of C. albicans, which also develops specific strategies to respond to the attack by NETs. Our review specifically focuses on the mechanisms by which C. albicans triggers NET formation and their subsequent interactions, which might provide meaningful insight into the innate immunity against C. albicans infection.

Boric Acid Solution Inhibits Candida albicans Infections in Mouse Skin via the IL-23/Th17 Axis.

The purpose of this study was to investigate the effect and mechanism of 3% boric acid solution (BAS) against Candida albicans (CA) infection via the interleukin-23 (IL-23)/T helper 17 cell (Th17) axis. 36 female mice were randomly divided into 3 groups, and 2 injection sites on the back of the mice were chosen at random. Group N was injected with sterile water for injection (SWFI), and Group M and Group B were injected with CA mycelium suspension. After successful model verification, the remaining mice entered the following treatments 5 days later. Group B was treated with 3% BAS, Group M was treated with SWFI, and Group N was not treated. Levels of interleukin-17 (IL-17), IL-22, and IL-23 in mouse blood were measured on days 1, 3, 5, and 7 of treatment. On day 7, IL-17, IL-22, and IL-23 in mouse skin were detected. Serum levels of IL-17, IL-22, and IL-23 in Group M were higher than in Group N on the first day of treatment (p < 0.05). Expression levels of IL-17, IL-22, and IL-23 in the epidermis of the skin lesions in Group M were higher than in Group N on day 7 (p < 0.05). The serum level of IL-17 in Group B was higher than in Group M on days 5 and 7 (p < 0.05). Serum levels of IL-22 in Group B on days 1, 5, and 7 were higher than in Group M (p < 0.05). Serum levels of IL-23 in Group B were higher than in Group M on days 3, 5, and 7 (p < 0.05). IL-17 and IL-23 in Group B reached a peak on day 5, significantly different on days 1, 3, and 7 (p < 0.05). The expression intensity of IL-17, IL-22, and IL-23 in the skin lesions of Group B was higher than that of Group M on day 7 (p < 0.05). We conclude that IL-17, IL-22, and IL-23 are involved in the anti-CA activity in mouse skin, and 3% BAS increased IL-17, IL-22, and IL-23 to mediate these effects.

Abstract 3044: C. albicans infection mediates upper gastrointestinal tract malignancy independently of Il17a in an APECED-like mouse model

Abstract Patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) develop chronic mucocutaneous candidiasis during childhood and about 10% of senior patients develop upper GI tract squamous cell carcinoma (SCC), suggesting that C. albicans infection may be relevant to the cause of SCC development in APECED patients. In this study, we investigated the role of C. albicans infection in upper GI tract SCC development using an APECED-like IKKα kinase-dead (KA/KA) mouse model. We found that KA/KA mice developed upper GI tract SCC after oral infection of WT C. albicans weekly for three months. Interestingly, while upper GI tract SCC development in C. albicans - infected KA/KA mice is IL-17a-independent, EGFR pathway plays an important role in C. albicans infection-mediated tumorigenesis in KA/KA mice, as evidenced by significantly lower SCC incidence in the upper GI tract of KA/KA mice infected with Als3Δ/Δ C. albicans. Moreover, upper GI tract SCCs from WT C. albicans-infected KA/KA mice exhibited robust p-EGFR and Ki67 signals. However, both p-EGFR and Ki67 signals were only mildly increased in upper GI tract of Als3Δ/Δ C. albicans-infected KA/KA mice compared to WT control mice. Meanwhile, EGFR inhibition dramatically reduced C. albicans colonization in upper GI tract and the weight of stomach in KA/KA mice. Furthermore, we found that aberrant infiltrations of neutrophils and macrophages with significant inflammatory signatures were present in the upper GI tract SCCs in KA/KA mice. Interestingly, KA/KA neutrophils exhibited a defect in C. albicans killing capacity due to functional defects in ROS generation, degranulation, NETs formation, and apoptosis. We reasoned that KA/KA neutrophils’ inability in C. albicans killing capacity may further enhance the tumor-promoting microenvironment. Finally, whole genome sequencing data suggested that C. albicans infection may lead to genome instability. Currently we are investigating the role of neutrophil infiltration in C. albicans infection-mediated upper GI tract tumorigenesis. Citation Format: Feng Zhu, Quynh T. Phan, Elise M. Ferre, Jami Willette-Brown, Rosalba Salcedo, Tsai-Wei Shen, Yu Fan, Yongmei Zhao, Monika Mehta, Daoud Meerzaman, Bao Tran, Giorgio Trinchieri, Michail S. Lionakis, Scott G. Filler, Yinling Hu. C. albicans infection mediates upper gastrointestinal tract malignancy independently of Il17a in an APECED-like mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3044.

Exposure of Keratinocytes to Candida Albicans in the Context of Atopic Milieu Induces Changes in the Surface Glycosylation Pattern of Small Extracellular Vesicles to Enhance Their Propensity to Interact With Inhibitory Siglec Receptors.

Candida albicans (C. albicans) infection is a potential complication in the individuals with atopic dermatitis (AD) and can affect clinical course of the disease. Here, using primary keratinocytes we determined that atopic milieu promotes changes in the interaction of small extracellular vesicles (sEVs) with dendritic cells and that this is further enhanced by the presence of C. albicans. sEV uptake is largely dependent on the expression of glycans on their surface; modelling of the protein interactions indicated that recognition of this pathogen through C. albicans-relevant pattern recognition receptors (PRRs) is linked to several glycosylation enzymes which may in turn affect the expression of sEV glycans. Here, significant changes in the surface glycosylation pattern, as determined by lectin array, could be observed in sEVs upon a combined exposure of keratinocytes to AD cytokines and C. albicans. This included enhanced expression of multiple types of glycans, for which several dendritic cell receptors could be proposed as binding partners. Blocking experiments showed predominant involvement of the inhibitory Siglec-7 and -9 receptors in the sEV-cell interaction and the engagement of sialic acid-containing carbohydrate moieties on the surface of sEVs. This pointed on ST6 β-Galactoside α-2,6-Sialyltransferase 1 (ST6GAL1) and Core 1 β,3-Galactosyltransferase 1 (C1GALT1) as potential enzymes involved in the process of remodelling of the sEV surface glycans upon C. albicans exposure. Our results suggest that, in combination with atopic dermatitis milieu, C. albicans promotes alterations in the glycosylation pattern of keratinocyte-derived sEVs to interact with inhibitory Siglecs on antigen presenting cells. Hence, a strategy aiming at this pathway to enhance antifungal responses and restrict pathogen spread could offer novel therapeutic options for skin candidiasis in AD.

Bile Acid Regulates Mononuclear Phagocytes and T Helper 17 Cells to Control Candida albicans in the Intestine.

Invasive Candida albicans (CA) infections often arise from the intestine and cause life-threatening infections in immunocompromised individuals. The role of gut commensal microbiota, metabolites, and host factors in the regulation of CA colonization in the intestine is poorly understood. Previous findings from our lab indicate that taurocholic acid (TCA), a major bile acid present in the intestine, promotes CA colonization and dissemination. Here, we report that oral administration of TCA to CA-infected mice significantly decreased the number of mononuclear phagocytes and CD4+ IL17A+ T helper 17 cells that play a critical role in controlling CA in the intestine. Collectively, our results indicate that TCA modulates mucosal innate and adaptive immune responses to promote CA colonization in the intestine.

Prediction of Prognostic Risk Factors in Patients with Invasive Candidiasis and Cancer: A Single-Centre Retrospective Study.

Background Invasive candidiasis is a common cancer-related complication with a high fatality rate. If patients with a high risk of dying in the hospital are identified early and accurately, physicians can make better clinical judgments. However, epidemiological analyses and mortality prediction models of cancer patients with invasive candidiasis remain limited. Method A set of 40 potential risk factors was acquired in a sample of 258 patients with both invasive candidiasis and cancer. To begin, risk factors for Candida albicans vs. non-Candida albicans infections and persistent vs. nonpersistent Candida infections were analysed using classic statistical methods. Then, we applied three machine learning models (random forest, logistic regression, and support vector machine) to identify prognostic indicators related to mortality. Prediction performance of different models was assessed by precision, recall, F1 score, accuracy, and AUC. Results Of the 258 patients both with invasive candidiasis and cancer included in the analysis. The median age of patients was 62 years, and 95 (36.82%) patients were older than 65 years, of which 178 (66.28%) were male. And 186 (72.1%) patients underwent surgery 2 weeks before data collection, 100 (39.1%) patients stayed in ICU during hospitalisation, 99 (38.4%) patients had bacterial blood infection, 85 (32.9%) patients had persistent invasive candidiasis, and 41 (15.9%) patients died within 30 days. The usage of drainage catheter and prolonged length of hospitalisation are the dominant risk factors for non-Candida albicans infections and persistent Candida infections, respectively. Risk factors, such as septic shock, history of surgery within the past 2 weeks, usage of drainage tubes, length of stay in ICU, total parenteral nutrition, serum creatinine level, fungal antigen, stay in ICU during hospitalisation, and total bilirubin level, were significant predictors of death. The RF model outperformed the LR and SVM models. Precision, recall, F1 score, accuracy, and AUC for RF were 64.29%, 75.63%, 69.23%, 89.61%, and 91.28%. Conclusions In this study, the machine learning-based models accurately predicted the prognosis of cancer and invasive candidiasis patients. The algorithm could be used to help clinicians in high-risk patients' early intervention.

Molecular docking analysis of Allium chinense compounds as Secreted Aspartyl Proteinase-5 (SAP5) inhibitor

Secreted Aspartyl Proteinase-5 (SAP5) or candidapepsin-5 is known as the current and major virulence factor in the biofilm formation of Candida albicans. The protein is secreted into the environment to disrupt the host immune cells and degrade keratin then penetrating the host defense to express its pathogenicity. SAPs has been targeted for many studies including in vitro test and in silico analysis of potential inhibitory agents. In the current study, we tested six selected compounds in the aqueous extract of Allium chinense G. Don. namely 1-tetradecanol, anozol, hyacinthin, isosorbide, mannitan and oleic acid for in silico analysis along with pepstatin A as the most potent inhibitor or control. The results obtained that oleic acid displayed the most stable bonding with the SAP5 based on molecular docking, visualization and data analysis although slightly lower than anozol in terms of binding affinity. Oleic acid also produced the most similar number of binding residues with pepstatin A based on 2D feature with also similar region in the pocket of SAP5 based on 3D visualization. Hence, the compound may be potentially developed as leading compound in treating C. albicans infections.

Antifungal effect of a new photosensitizer derived from BODIPY on Candida albicans biofilms

BackgroundPhotodynamic therapy (PDT) may be an alternative treatment of Candida albicans (C. albicans) infections. The aim of this study was to investigate the antifungal effect of PDT mediated by a new photosensitizer (PS) derived from BODIPY (BDP-4L) on C. albicans biofilms. MethodsC. albicans biofilms were incubated with BDP-4L of different concentrations and then irradiated at the light doses of 1.8, 3.6, 5.4, 7.2 and 9.0 J/cm2. XTT reduction assay was conducted to determine the PS concentration and PDT parameters. Confocal light scanning microscopy (CLSM) and scanning electron microscope (SEM) were used to visualize and quantify the effect of BDP-4L on C. albicans biofilms after PDT. ResultsC. albicans biofilms were inactivated in light dose-dependent and PS concentration-dependent manners using BDP-4L as PS. Without irradiation, no inactivation effect was observed when PS concentrations varied from 5 μM to 80 μM. 40 μM PS with 3.6 J/cm2 irradiation resulted in a significant reduction of 83.8% in biofilm metabolic activities. CLSM assay demonstrated that cell viability was obviously inhibited by 82.6%. SEM images revealed ruptured and rough cell surface, indicating increased cell membrane permeability after PDT. ConclusionsOur results suggested that BDP-4L mediated PDT exhibited a favorable antifungal effect on C. albicans biofilms.

Phagolysosomal remodeling to confine Candida albicans in the macrophage.

Macrophages play a crucial role in fungal clearance during Candida albicans infection. In order to eliminate the intracellular fungi and survive, macrophages need to quickly respond to the dimorphic transition by repairing the phagolysosomal membrane. Also, actin-contractile rings were recently suggested as a powerful weapon to dampen hyphal growth.

Candida albicans Hyphal Extracellular Vesicles Are Different from Yeast Ones, Carrying an Active Proteasome Complex and Showing a Different Role in Host Immune Response.

ABSTRACTCandida albicans is the principal causative agent of lethal fungal infections, predominantly in immunocompromised hosts. Extracellular vesicles (EVs) have been described as crucial in the interaction of microorganisms with their host. Since the yeast-to-hypha transition is an important virulence trait with great impact in invasive candidiasis (IC), we have addressed the characterization of EVs secreted by hyphal cells (HEVs) from C. albicans, comparing them to yeast EVs (YEVs). YEVs comprised a larger population of bigger EVs with mainly cell wall proteins, while HEVs were smaller, in general, and had a much higher protein diversity. YEVs were able to rescue the sensitivity of a cell wall mutant against calcofluor white, presumably due to the larger amount of cell wall proteins they contained. On the other hand, HEVs also contained many cytoplasmic proteins related to protein metabolism and intracellular protein transport and the endosomal sorting complexes required for transport (ESCRT) pathway related to exosome biogenesis, pointing to an intracellular origin of HEVs. Interestingly, an active 20S proteasome complex was secreted exclusively in HEVs. Moreover, HEVs contained a greater number of virulence-related proteins. As for their immunogenic role, both types of EV presented immune reactivity with human sera from patients suffering invasive candidiasis; however, under our conditions, only HEVs showed a cytotoxic effect on human macrophages and could elicit the release of tumor necrosis factor alpha (TNF-α) by these macrophages.IMPORTANCE This first analysis of HEVs of C. albicans has shown clear differences between them and the YEVs of C. albicans, showing their relevance and possible use in the discovery of new diagnostic markers and treatment targets against C. albicans infections. The data obtained point to different mechanisms of biogenesis of YEVs and HEVs, as well as different involvements in cell biology and host interaction. YEVs played a more relevant role in cell wall maintenance, while HEVs were more closely related to virulence, as they had greater effects on human immune cells. Importantly, an active 20S proteosome complex was described as a fungal-EV cargo. A deeper study of its role and those of many other proteins exclusively detected in HEVs and involved in different relevant biological processes of this fungus could open up interesting new areas of research in the battle against C. albicans.

Potential of Polyethyleneimine as an Adjuvant To Prepare Long-Term and Potent Antifungal Nanovaccine

Background Candida albicans infections are particularly prevalent in immunocompromised patients. Even with appropriate treatment with current antifungal drugs, the mortality rate of invasive candidiasis remains high. Many positive results have been achieved in the current vaccine development. There are also issues such as the vaccine’s protective effect is not persistent. Considering the functionality and cost of the vaccine, it is important to develop safe and efficient new vaccines with long-term effects. In this paper, an antifungal nanovaccine with Polyethyleneimine (PEI) as adjuvant was constructed, which could elicit more effective and long-term immunity via stimulating B cells to differentiate into long-lived plasma cells.Materials and MethodsHsp90-CTD is an important target for protective antibodies during disseminated candidiasis. Hsp90-CTD was used as the antigen, then introduced SDS to “charge” the protein and added PEI to form the nanovaccine. Dynamic light scattering and transmission electron microscope were conducted to identify the size distribution, zeta potential, and morphology of nanovaccine. The antibody titers in mice immunized with the nanovaccine were measured by ELISA. The activation and maturation of long-lived plasma cells in bone marrow by nanovaccine were also investigated via flow cytometry. Finally, the kidney of mice infected with Candida albicans was stained with H&E and PAS to evaluate the protective effect of antibody in serum produced by immunized mice.ResultsNanoparticles (NP) formed by Hsp90-CTD and PEI are small, uniform, and stable. NP had an average size of 116.2 nm with a PDI of 0.13. After immunizing mice with the nanovaccine, it was found that the nano-group produced antibodies faster and for a longer time. After 12 months of immunization, mice still had high and low levels of antibodies in their bodies. Results showed that the nanovaccine could promote the differentiation of B cells into long-lived plasma cells and maintain the long-term existence of antibodies in vivo. After immunization, the antibodies in mice could protect the mice infected by C. albicans.ConclusionAs an adjuvant, PEI can promote the differentiation of B cells into long-lived plasma cells to maintain long-term antibodies in vivo. This strategy can be adapted for the future design of vaccines.

In vitro and in vivo Activity of Phibilin Against Candida albicans.

The increase in the occurrence of antifungal-resistant Candida albicans infections necessitates more research to explore alternative effective and safe agents against this fungus. In this work, Phibilin, a new antimicrobial peptide obtained from Philomycus bilineatus and used in traditional Chinese medicine, effectively inhibits the growth and activities of C. albicans, including the clinical resistant strains. Phibilin is a fungicidal antimicrobial peptide that exhibited its antimicrobial effect against C. albicans mainly by disrupting the membrane and interacting with the DNA of the fungi. In particular, Phibilin induces the necrosis of C. albicans via the ROS-related pathway. Moreover, this antifungal compound inhibited the biofilm formation of C. albicans by preventing the development of hyphae in a dose-dependent manner. Furthermore, Phibilin and clotrimazole displayed a synergistic effect in inhibiting the growth of the fungi. In the mouse cutaneous infection model, Phibilin significantly inhibited the formation of skin abscesses and decreased the counts of C. albicans cells in the infected area. Overall, Phibilin is potentially an effective agent against skin infections caused by C. albicans.

Dermatomycoses in Pakistan; an urgent need for National Surveillance Programs

Despite the rising burden of fungal infections across the globe, the World Health Organization's efforts remained questionable in fungal infection-related projects. Most of the developing countries consequently lost focus on the need for assessment and establishment of national surveillance set up or advanced technology hubs against mycological infections. The current study aimed to the determination of the local burden of cutaneous fungal infections in 2019-2021. Among 497 suspected fungal cultures, 22.5% depicted fungal growth. Among males, the prevalence of dermatomycosis was 0.75 times higher than in females. Penicillium species followed by Epidermophyton and Candida species were common among subjects of &lt; 30 years of age. The Aspergillus spp, Penicillium spp, mucormycosis agents, and Candida albicans infections were more common among subjects 30 to 60 years of age. Aspergillus species were more commonly observed among patients &gt; 60 of age. 22.2% of the fungal infections were Penicillium species, 9% of the infections were Aspergillus species, followed by 4.4% of Epidermophyton, mucormycosis, Candida species, and Candida albicans respectively. There is an urgent need for the establishment of national policy for the prevention of fungal disease.

Small, Cationic Antifungal Proteins from Filamentous Fungi Inhibit Candida albicans Growth in 3D Skin Infection Models.

ABSTRACTThe emerging resistance of human-pathogenic fungi to antifungal drugs urges the development of alternative therapeutic strategies. The small, cationic antifungal proteins (AFPs) from filamentous ascomycetes represent promising candidates for next-generation antifungals. These bio-molecules need to be tested for tolerance in the host and efficacy against fungal pathogens before they can be safely applied in humans. Testing of the efficacy and possible adverse effects of new drug candidates in three-dimensional (3D) human-cell based models represents an advantageous alternative to animal experiments. In, this study, as a proof-of-principle, we demonstrate the usefulness of 3D skin infection models for screening new antifungal drug candidates for topical application. We established a cutaneous infection with the opportunistic human-pathogenic yeast Candida albicans in a commercially available 3D full-thickness (FT) skin model to test the curative potential of distinct AFPs from Penicillium chrysogenum (PAFopt, PAFB, and PAFC) and Neosartorya (Aspergillus) fischeri (NFAP2) in vitro. All tested AFPs were comparably well tolerated by the skin models. The infected 3D models exhibited reduced epidermal permeability barriers, allowing C. albicans to colonize the epidermal and dermal layers, and showed increased secretion of the pro-inflammatory cytokine IL-6 and the chemokine IL-8. AFP treatment diminished the fungal burden and penetration depth of C. albicans in the infected models. The epidermal permeability barrier was restored and the secretion of IL-8 was decreased following AFP treatment. In summary, our study proves that the tested AFPs exhibit antifungal potential against cutaneous C. albicans infection in a 3D FT skin model.IMPORTANCE Candida albicans represents one of the most prevalent opportunistic fungal pathogens, causing superficial skin and mucosal infections in humans with certain predisposing health conditions and life-threatening systemic infections in immunosuppressed patients. The emerging drug resistance of this human-pathogenic yeast and the limited number of antifungal drugs for prevention and treatment of infections urgently demands the identification of new antifungal compounds with novel mechanisms of action. Small, cationic antifungal proteins (AFPs) from filamentous fungi represent promising candidates for next-generation antifungals for topical application. These bio-molecules need to be tested for tolerance by the host and efficacy in pathogen clearance prior to being involved in clinical trials. In a proof-of-principle study, we provide evidence for the suitability of 3D human-cell based models as advantageous alternatives to animal experiments. We document the tolerance of specific AFPs and their curative efficacy against cutaneous C. albicans infection in a 3D skin model.