Isorhamnetin Ameliorates Aspergillus fumigatus Keratitis by Reducing Fungal Load, Inhibiting Pattern-Recognition Receptors and Inflammatory Cytokines

Chelerythrine ameliorates Aspergillus fumigatus keratitis through suppressing the LOX-1/p38 MAPK signaling pathway

PURPOSE

Aspergillus fumigatus (A. fumigatus) keratitis is a type of infectious corneal disease that significantly impairs vision. The objective of this study is to evaluate the therapeutic potential of chelerythrine (CHE) on A. fumigatus keratitis.

METHODS

The antifungal activity of CHE was assessed through various tests including the minimum inhibitory concentration test, scanning electron microscopy, transmission electron microscopy, propidium iodide uptake test and plate count. Neutrophil infiltration and activity were assessed using immunofluorescence staining and the myeloperoxidase test. RT-PCR, western blotting assay, and ELISA were performed to measure the expression levels of proinflammatory cytokines (IL-1β and IL-6), NF-E2-related factor (Nrf2), heme oxygenase-1 (HO-1), and lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), as well as to determine the ratio of phosphorylated-p38 (p-p38) mitogen-activated protein kinase (MAPK) to p38 MAPK.

RESULTS

In vitro, CHE inhibited the growth of A. fumigatus conidia, reduced fungal hyphae survival, and prevented fungal biofilm formation. In vivo, CHE reduced the severity of A. fumigatus keratitis and exhibited an excellent anti-inflammatory effect by blocking neutrophil infiltration. Furthermore, CHE decreased the expression levels of proinflammatory cytokines and LOX-1 at both mRNA and protein levels, while also decreasing the p-p38 MAPK/p38 MAPK ratio. Additionally, CHE increased the expression levels of Nrf2 and HO-1.

CONCLUSION

CHE provides protection against A. fumigatus keratitis through multiple mechanisms, including reducing fungal survival, inducing anti-inflammatory effects, enhancing Nrf2 and HO-1 expression, and suppressing the signaling pathway of LOX-1/p38 MAPK.

Liquiritin Alleviates Inflammation in Lipopolysaccharide-Induced Human Corneal Epithelial Cells

PURPOSE

This research was designed to elucidate the anti-inflammatory impacts of liquiritin on lipopolysaccharide (LPS)-activated human corneal epithelial cells (HCECs).

METHODS

The Cell Counting kit-8 (CCK-8) assay was adopted to assess cell viability. The enzyme-linked immunosorbent assay (ELISA) was used to detect the secretion levels of the proinflammatory cytokines IL-6, IL-8, and TNF-α. Transcriptome analysis was conducted to identify the genes that exhibited differential expression between different treatment. The model group included cells treated with LPS (10 µg/mL), the treatment group comprised cells treated with liquiritin (80 µM) and LPS (10 µg/mL), and the control group consisted of untreated cells. To further validate the expression levels of the selected genes, including CSF2, CXCL1, CXCL2, CXCL8, IL1A, IL1B, IL24, IL6, and LTB, quantitative real-time PCR was performed. The expression of proteins related to the Akt/NF-κB signaling pathway was assessed through western blot analysis. NF-κB nuclear translocation was evaluated through immunofluorescence staining.

RESULTS

The secretion of IL-6, IL-8, and TNF-α in LPS-induced HCECs was significantly downregulated by liquiritin. Based on the transcriptome analysis, the mRNA expression of pro-inflammatory cytokines, namely IL-6, IL-8, IL-1β, IL-24, TNF-α, and IL-1α was overproduced by LPS stimulation, and suppressed after liquiritin treatment. Furthermore, the Western blot results revealed a remarkable reduction in the phosphorylation degrees of NF-κB p65, IκB, and Akt upon treatment with liquiritin. Additionally, immunofluorescence analysis confirmed liquiritin's inhibition of LPS-induced p65 nuclear translocation.

CONCLUSIONS

Collectively, these findings imply that liquiritin suppresses the expression of proinflammatory cytokines, and the anti-inflammatory impacts of liquiritin may be caused by its repression of the Akt/NF-κB signaling pathway in LPS-induced HCECs. These data indicate that liquiritin could provide a potential therapeutic application for inflammation-associated corneal diseases.

In vitro and ex vivo models of microbial keratitis: Present and future

Microbial keratitis (MK) is an infection of the cornea, caused by bacteria, fungi, parasites, or viruses. MK leads to significant morbidity, being the fifth leading cause of blindness worldwide. There is an urgent requirement to better understand pathogenesis in order to develop novel diagnostic and therapeutic approaches to improve patient outcomes. Many in vitro, ex vivo and in vivo MK models have been developed and implemented to meet this aim. Here, we present current in vitro and ex vivo MK model systems, examining their varied design, outputs, reporting standards, and strengths and limitations. Major limitations include their relative simplicity and the perceived inability to study the immune response in these MK models, an aspect widely accepted to play a significant role in MK pathogenesis. Consequently, there remains a dependence on in vivo models to study this aspect of MK. However, looking to the future, we draw from the broader field of corneal disease modelling, which utilises, for example, three-dimensional co-culture models and dynamic environments observed in bioreactors and organ-on-a-chip scenarios. These remain unexplored in MK research, but incorporation of these approaches will offer further advances in the field of MK corneal modelling, in particular with the focus of incorporation of immune components which we anticipate will better recapitulate pathogenesis and yield novel findings, therefore contributing to the enhancement of MK outcomes.

Therapeutic effect of oxidized bletilla striata polysaccharide-natamycin eye drops on fungal keratitis

OBJECTIVE

Fungal keratitis (FK) usually develops to a poor clinical prognosis due to the fungal invasion and excessive inflammatory reaction. In order to enhance the therapeutic effect of natamycin (NAT), we used the anti-inflammatory biological polysaccharide bletilla striata polysaccharide (BSP) combined with NAT to prepare a new eye drop -- oxidized bletilla striata polysaccharide-natamycin (OBN).

METHODS

UV-vis, FT-IR, and fluorescence spectroscopy were used to identify the synthesis of OBN. Biocompatibility of OBN was determined by CCK-8, scratch assay, and corneal toxicity test. RAW264.7 cells and C57BL/6 mice were stimulated with A. fumigatus and treated with PBS, OBN, or NAT. The anti-inflammatory activity of OBN was detected by RT-PCR and ELISA. In mice with FK, the clinical scores were used to evaluate the effect of OBN; HE staining was performed to assess the corneal pathological changes; MPO assay and immunofluorescence staining were used to investigate neutrophil infiltration.

RESULTS

OBN was synthesized by combining oxidized bletilla striata polysaccharide (OBSP) with NAT through Schiff base reaction. OBN did not affect cell viability at a concentration of 160 μg/mL in HCECs, RAW264.7 cells, and mouse corneas. OBN versus NAT significantly improved the prognosis of A. fumigatus keratitis by reducing disease severity, neutrophil infiltration, and expression of inflammatory factors in vivo. Additionally, OBN treatment down-regulated the mRNA and protein expression levels of inflammatory factors IL-1β, TNF-α, and IL-6 in RAW264.7 and mouse models.

CONCLUSION

OBN is a compound prepared by covalently linking OBSP to the imino group of NAT through Schiff base reaction. OBN treatment down-regulated inflammation and improved the prognosis of mice with A. fumigatus keratitis.

Resveratrol has neuroprotective effects and plays an anti-inflammatory role through Dectin-1/p38 pathway in Aspergillus fumigatus keratitis

PURPOSE

To determine the antifungal, anti-inflammatory and neuroprotective effects of resveratrol (RES) in Aspergillus fumigatus (A. fumigatus) keratitis.

METHODS

Cytotoxicity assay and Draize eye assay were performed to assess the toxicity of RES. The antifungal effect of RES was assessed by minimal inhibitory concentration, scanning or transmission electron microscopy, propidium iodide uptake assay, and Calcofluor white staining. Phosphorylation of p38 MAPK, mRNA and protein levels of Dectin-1 and related inflammatory factors were measured by qRT-PCR, ELISA and Western blot in vitro and in vivo. Clinical score, HE staining, plate count, and myeloperoxidase test were used to observe the progress of fungal keratitis. IF staining, qRT-PCR, and the Von Frey test were selected to assess the neuroprotective effects of RES.

RESULTS

RES suppressed A. fumigatus hyphae growth and altered hyphae morphology in vitro. RES decreased the expression of Dectin-1, IL-1β and TNF-α, as well as p38 MAPK phosphorylation expression, and also decreased clinical scores, reduced inflammatory cell infiltration and neutrophil activity, and decreased fungal load. RES also protected corneal basal nerve fibers, down-regulated mechanosensitivity thresholds, and increased the mRNA levels of CGRP and TRPV-1..

CONCLUSION

These evidences revealed that RES could exert antifungal effects on A. fumigatus and ameliorate FK through suppressing the Dectin-1/p38 MAPK pathway to down-regulate IL-1β, IL-6, etc. expression and play protective effect on corneal nerves.

Isorhamnetin ameliorates cisplatin-induced acute kidney injury in mice by activating SLPI-mediated anti-inflammatory effect in macrophage

OBJECTIVE

Isorhamnetin (IH) has been reported to have significant anti-inflammatory effects in various diseases, but its role and mechanism in AKI remain unclear. This study aimed to explore the potential role and mechanism of isorhamnetin in inhibiting macrophage related inflammation and improving AKI injury.

METHODS

We established an AKI mouse model by intraperitoneal injection of cisplatin in vivo, and constructed an inflammatory cell model by stimulating RAW264.7 cells with LPS. Creatinine and urea nitrogen were measured to evaluate the changes of renal function in AKI mice. The changes of renal pathological structure were observed by H&E staining. The inflammatory factor-related proteins and RNA expression levels were detected by Western blot and real time PCR.

RESULTS

Isorhamnetin protected the kidney from cisplatin induced AKI and significantly inhibited the mRNA and protein levels of inflammatory cytokines (IL-1β, IL-6, and TNF-α) both in AKI kidney and LPS-stimulated RAW264.7 cells. Interestingly, the data also demonstrated that isorhamnetin significantly upregulated the expression of secretory leukocyte peptidase inhibitor (SLPI), an anti-inflammatory factor, in AKI kidney and LPS-stimulated macrophages, as well as inhibited the M1 macrophage and activated M2 macrophage in vitro. Blocking of SLPI by siRNA activated Mincle-associated inflammatory signaling in macrophages, and the inhibitory effect of isorhamnetin on inflammation was significantly attenuated.

CONCLUSION

Isorhamnetin inhibits macrophage inflammation and protects kidney in AKI may be related to downregulating Mincle/Syk/NF-κB-maintained macrophage phenotype by activating SLPI.

Oxymatrine mitigates Aspergillus fumigatus keratitis by suppressing fungal activity and restricting pyroptosis

Fungal keratitis (FK) is a refractory keratitis caused by excessive inflammation and fungal damage. Excessive inflammation can lead to tissue damage and corneal opacity, resulting in a poor prognosis for FK. Oxymatrine (OMT) is a natural alkaloid, which has rich pharmacological effects, such as antioxidant and anti-inflammation. However, its antifungal activity and the mechanism of action in FK have not been elucidated. This study confirmed that OMT suppressed Aspergillus fumigatus growth, biofilm formation, the integrity of fungal cell and conidial adherence. OMT not only effectively reduced corneal fungal load but also inflammation responses. OMT lessened the recruitment of neutrophils and macrophages in FK. In addition, OMT up-regulated the expression of Nrf2 and down-regulated the expression of IL-18, IL-1β, caspase-1, NLRP3 and GSDMD. Pre-treatment with Nrf2 inhibitor up-regulated the expression of IL-1β, IL-18, caspase-1, NLRP3 and GSDMD supressed by OMT. In conclusion, OMT has efficient anti-inflammatory and antifungal effects by suppressing fungal activity and restricting pyroptosis via Nrf2 pathway. OMT is considered as a potential option for the treatment of FK.

Comprehensive and critical view on the anti-inflammatory and immunomodulatory role of natural phenolic antioxidants

The immune response encompasses innate and adaptive immunity, each with distinct and specific activities. The innate immune system is constituted by phagocytic cells, macrophages, monocytes and neutrophils, the cascade system, and different classes of receptors such as toll-like receptors that are exploited by the innate immune cells. The adaptive immune system is antigen-specific, encompassing memory lymphocytes and the corresponding specific receptors. Inflammation is understood as an activation of different signaling pathways such as toll-like receptors or nuclear factor kappa-light-chain-enhancer of activated B cells, with an increase in nitric oxide, inflammatory cytokines and chemokines. Increased oxidative stress has been identified as main source of chronic inflammation. Phenolic antioxidants modulate the activities of lymphocytes and macrophages by impacting cytokines and nitric oxide release, exerting anti-inflammatory effect. The nuclear-factor kappa-light-chain-enhancer of activated B cells signaling pathway and the mitogen-activated protein kinase pathway are targeted, alongside an increase in nuclear factor erythroid 2-related factor mediated antioxidant response, triggering the activity of antioxidant enzymes. The inhibitive potential on phospholipase A2, cyclooxygenase and lipoxygenase in the arachidonic acid pathway, and the subsequent reduction in prostaglandin and leukotriene generation, reveals the potential of phenolics as inflammation antagonists. The immunomodulative potential encompasses the capacity to interfere with proinflammatory cytokine synthesis and with the expression of the corresponding genes. A diet rich in antioxidants can result in prevention of inflammation-related pathologies. More investigations are necessary to establish the role of these antioxidants in therapy. The appropriate delivery system and the prooxidant effects exhibited at large doses, or in the presence of heavy metal cations should be regarded.

The effect of Astragali Radix-Radix Angelica Sinensis on acute kidney injury: a network pharmacology and molecular docking study

Background

Acute kidney injury (AKI) is a devastating clinical syndrome with high mortality rate attributed to lack of effective treatment. The herbal pair of Astragali Radix (AR) and Radix Angelica Sinensis (RAS) is a commonly prescribed herbal formula or is added to other traditional Chinese medicine (TCM) prescriptions for the treatment of kidney diseases. AR-RAS has certain protective effects on AKI in experiments, but the relevant mechanisms have yet to be clear. So this study aims to explore the mechanism of action of AR-RAS in AKI by combining network pharmacology and molecular docking methods.

Methods

In Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), the major AR-RAS chemical components and associated action targets were found and screened. The DrugBank and GeneCards databases were used to find AKI-related targets. The targets that are in close relationship with AKI were obtained from Therapeutic Target database (TTD), Online Mendelian Inheritance in Man (OMIM), and PharmGKB databases. The "herb-active ingredient-target" network was drawn by Cytoscape 3.8.0 software. The Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database was used to build the protein-protein interaction network. Bioconductor/R was used to examine Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. AR-RAS components and critical targets were docked using the AutoDock Vina program.

Results

A compound-target network, built by screening and analyzing the results, allowed to identify 19 active components and 101 possible therapeutic targets for AKI. The main ingredients were quercetin, kaempferol, 7-o-methylisocronulatol, formononetin and isorhamnetin. The key targets included AKT serine/threonine kinase 1 (AKT1), nuclear receptor coactivator 1 (NCOA1), JUN, estrogen receptor alpha (ESR1) and mitogen-activated protein kinase 8 (MAPK8). These molecules are targeted by pathways such as the calcium signaling route, the tumor necrosis factor (TNF) signaling pathway and the interleukin-17 (IL-17) signaling pathway, as well as the development of T helper 17 cells. Molecular docking demonstrated that AR-active RAS components exhibited strong binding activities to probable targets of AKI.

Conclusions

We described here the potential active ingredients, possible targets responsible for the efficacy of AR-RAS in AKI treatment, providing a theoretical basis for further research.

The Therapeutic Role and Mechanism of Glabridin Under Aspergillus fumigatus Infection

Purpose: To characterize the efficiency of glabridin alone and in combination with clinical antifungals in Aspergillus fumigatus keratitis. Methods: The broth microdilution method was performed to investigate whether glabridin exerted an antifungal role on planktonic cells and immature and mature biofilm. Antifungal mechanism was evaluated by Sorbitol and Ergosterol Assays. The synergistic effect of glabridin and antifungals was assessed through the checkerboard microdilution method and time-killing test. Regarding anti-inflammatory role, inflammatory substances induced by A. fumigatus were assessed by real-time quantitative polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay. Drug toxicity was assessed by Draize test in vivo. Macrophage phenotypes were examined by flow cytometry. Results: Regarding antifungal activity, glabridin destroyed fungal cell wall and membrane on planktonic cells and suppressed immature and mature biofilm formation. After combining with natamycin or amphotericin B, glabridin possessed a potent synergistic effect against A. fumigatus. Regarding anti-inflammatory aspects, Dectin-1, toll‑like receptor (TLR)-2 and TLR-4 expression of human corneal epithelial cells were significantly elevated after A. fumigatus challenge and reduced by glabridin. The elevated expression of interleukin-1β and tumor necrosis factor-alpha induced by A. fumigatus or corresponding agonists were reversed by glabridin, equivalent to the effect of corresponding inhibitors. Glabridin could also contribute to anti-inflammation by downregulating inflammatory mediator expression to suppress macrophage infiltration. Conclusions: Glabridin contributed to fungal clearance by destroying fungal cell wall and membrane, and disrupting biofilm. Combining glabridin with clinical antifungals was superior in reducing A. fumigatus growth. Glabridin exerted an anti-inflammatory effect by downregulating proinflammatory substance expression and inhibiting macrophage infiltration, which provide a potential agent and treatment strategies for fungal keratitis.

The potential benefits of polyphenols for corneal diseases

The cornea functions as the primary barrier of the ocular surface, regulating temperature and humidity while providing protection against oxidative stress, harmful stimuli and pathogenic microorganisms. Corneal diseases can affect the biomechanical and optical properties of the eye, resulting in visual impairment or even blindness. Due to their diverse origins and potent biological activities, plant secondary metabolites known as polyphenols offer potential advantages for treating corneal diseases owing to their anti-inflammatory, antioxidant, and antibacterial properties. Various polyphenols and their derivatives have demonstrated diverse mechanisms of action in vitro and in vivo, exhibiting efficacy against a range of corneal diseases including repair of tissue damage, treatment of keratitis, inhibition of neovascularization, alleviation of dry eye syndrome, among others. Therefore, this article presents a concise overview of corneal and related diseases, along with an update on the research progress of natural polyphenols in safeguarding corneal health. A more comprehensive understanding of natural polyphenols provides a novel perspective for secure treatment of corneal diseases.

Thymoquinone attenuates inflammation in C. Albicans keratitis by activating Nrf2/HO-1 signaling pathway and reducing fungal load

PURPOSE

This study aims to investigate the anti-inflammatory and antifungal properties of thymoquinone (TQ) and elucidate its mechanism of action in the context of C. albicans keratitis.

METHODS

Various methods were employed to identify a safe and effective concentration of TQ with antifungal properties, including the determination of the minimum inhibitory concentration (MIC), the cell counting kit-8 (CCK-8) test, and the Draize experiment. The severity of fungal keratitis (FK) was assessed through clinical ratings and slit-lamp imaging. Fungus burden was determined using plate counting and periodic acid Schiff (PAS) staining. Neutrophil infiltration and activity were investigated through immunofluorescence staining (IFS), myeloperoxidase (MPO) analysis, and hematoxylin and eosin (HE) staining. To explore the anti-inflammatory effects of TQ and its mechanism of action, we employed RT-PCR, ELISA, and western blot techniques.

RESULTS

TQ effectively controlled fungal growth at a concentration of 50 µg/mL while preserving the integrity of mouse corneas. Human corneal epithelial cells (HCECs) remained unaffected by TQ at concentrations ≤ 3.75 µg/mL. Treatment with TQ led to significant improvements in clinical scores, fungal burden, neutrophil infiltration, and the expression of inflammatory factors compared to the DMSO group. Moreover, TQ demonstrated the ability to reduce the levels of inflammatory factors in HCECs stimulated by C. albicans. Additionally, TQ enhanced the expressions of Nrf2 and HO-1 in mouse corneas. The downregulation of cytokines induced by TQ was reversed upon pretreatment with inhibitors of Nrf2 or HO-1.

CONCLUSION

TQ exhibits a protective effect in the context of C. albicans keratitis through multiple mechanisms, including inhibition of C. albicans growth, reduction of neutrophil recruitment, activation of the Nrf2/HO-1 pathway, and limitation of the expression of pro-inflammatory factors.

Biological activities of Viscum tuberculatum aqueous leaf extract

CONTENT

Plant-based natural products have served as sources of remedies against pathogenic microorganisms. Although the biological activities of Viscum (Santalaceae) species are widely recognized, there is no scientific evidence for Viscum tuberculatum A. Rich. in Ethiopia.

OBJECTIVE

To investigate the antimicrobial, acute toxicity, anti-inflammatory properties and phytochemical constituents of an aqueous extract of V. tuberculatum from Ethiopia.

MATERIALS AND METHODS

The antibacterial activity of the aqueous leaf extract of V. tuberculatum was tested against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of this extract were determined using the broth macrodilution method. The acute toxicity and anti-inflammatory effects of the extract were investigated using standard procedures on female and male white albino mice, aged 8 and 10 weeks, respectively. The phytochemical constituents of V. tuberculatum were determined using LC-MS QTOF.

RESULTS

The MIC and MBC values against S. aureus were found to be 6.25 and 100 mg/mL. The LD₅₀ value was more than 2000 mg/kg body weight of the mouse. The 400 mg/kg dose exerts 87% inhibition after 5 h of carrageenan injection. Twenty-five different metabolites, mainly flavonoids, phenolic acids and alkaloids, were identified.

CONCLUSIONS

These findings demonstrate the potential antimicrobial and anti-inflammatory potential of the aqueous extract of V. tuberculatum.

Quercetin protects against Aspergillus fumigatus keratitis by reducing fungal load and inhibiting TLR-4 induced inflammatory response

PURPOSE

To investigate the antifungal and anti-inflammatory effects of quercetin in Aspergillus fumigatus (A. fumigatus) keratitis.

METHODS

Draize eye test was performed in mice to evaluate the toxicity of quercetin, and the antifungal effects on A. fumigatus were assessed via scanning electron microscopy (SEM), propidium iodide uptake, and adherence assay. In fungal keratitis (FK) mouse models, immunostaining was performed for investigating toll-like receptor 4 (TLR-4) expression and macrophage infiltration. Real-time PCR, ELISA, and Western blot were used to evaluate the expression of pro-inflammatory factors IL-1β, TNF-α, and IL-6 in infected RAW264.7 cells. Cells were also treated with TLR-4 siRNA or agonist CRX-527 to investigate mechanisms underlying the anti-inflammatory activity of quercetin.

RESULTS

Quercetin at 32 μM was non-toxic to corneal epithelial and significantly inhibited A. fumigatus growth and adhesion, and also altered the structure and reduced the number of mycelia. Quercetin significantly reduced macrophage infiltration in the mouse cornea, and attenuated the expression of TLR-4 in the corneal epithelium and stroma of mice with keratitis caused by A. fumigatus. In RAW264.7 cells infected by A. fumigatus, quercetin downregulated TLR-4 along with pro-inflammatory factors IL-1β, TNF-α, and IL-6. RAW cells with TLR-4 knockdown had reduced expression of factors after A. fumigatus infection, which was decreased even further with quercetin treatment. In contrast, cells with CRX-527 had elevated inflammatory factors compared to control, which was significantly attenuated in the presence of quercetin.

CONCLUSION

Quercetin plays a protective role in mouse A. fumigatus keratitis by inhibiting fungal load, disrupting hyphae structure, macrophage infiltration, and suppressing inflammation response in macrophages via TLR-4 mediated signaling pathway.

0.01% Hypochlorous Acid Treats Aspergillus fumigatus Keratitis in Rats by Reducing Fungal Load and Inhibiting the Inflammatory Response

Purpose

To investigate the antifungal and anti-inflammatory effects of 0.01% hypochlorous acid (HCLO) on rats with Aspergillus fumigatus keratitis.

Methods

The time-kill assay and broth microdilution procedures were used in vitro to demonstrate that 0.01% HCLO was fungicidal and fungistatic. The severity of the disease was evaluated in vivo using a clinical score and slit-lamp photographs. Fungal load, polymorphonuclear neutrophil infiltration, and the production of related proteins were determined using colony plate counting, in vivo confocal microscopy, periodic acid-Schiff staining, fungal fluorescence staining, immunofluorescence staining, myeloperoxidase assay, and Western blotting.

Result

In vitro, 0.01% HCLO can destroy A. fumigatus spores in 1 minute. The optical density of the 0.01% HCLO group was significantly lower than that of the phosphate-buffered saline control group (P < 0.01), and no visible mycelium was observed using a fluorescence microscope. 0.01% HCLO reduced the severity of A. fumigatus keratitis in rats by decreasing the clinical score, fungal loading (periodic acid-Schiff, plate count, and fungal fluorescence staining), and inhibiting neutrophil infiltration and activity (immunofluorescence staining and myeloperoxidase). Furthermore, the Western blot analysis revealed that 0.01% HCO decreased protein expression levels of tumor necrosis factor-α and IL-1β.

Conclusions

According to our findings, 0.01% HCLO can kill A. fumigatus spores in vitro. It has antifungal and anti-inflammatory effects on A. fumigatus keratitis in rats. It also inhibited A. fumigatus growth; decreased neutrophil infiltration, tumor necrosis factor-α, and IL-1β expression; and provided a potential treatment for fungal keratitis.

Translational Relevance

This study provides a potential treatment for fungal keratitis in the clinic.

Chemical constituents and antifungal potential of Attalea geraensis Barb. Rodr. (Arecaceae) palm leaves, a species native to the Cerrado of Brazil

Fungal diseases, especially those that affect the root systems of plants, caused by Rhizoctonia and Macrophomina are limiting factors for achieving high crop yields. Alternatives to controlling fungi with chemical products drive the search for new options for bioactive compounds from plants. Attalea geraensis, a palm tree from the Brazilian Cerrado, is rich in flavonoids with antifungal actions. The objective of this work is to identify the chemical classes present in the ethanolic extract of green leaves of A. geraensis and determine the antifungal potential of the extract against isolates of Macrophomina phaseolina (Tassi) Goid. and Rhizoctonia solani JG Kühn. Phytochemical prospection, flavonoid dereplication, and antifungal activity were carried out of the ethanolic extract of the green leaves of A. geraensis harvested in the Cerrado area of Brazil. Steroids, triterpenes, saponins, and anthraquinones are described here for the first time for the leaves of A. geraensis. The flavonoids quercetin, isorhamnetin, 3,7-dimethylquercetin, quercetin 3-galactoside, 5,7-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-{[3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}-4H-chromen-4-one, rhamnazin 3-galactoside, keioside, and rhamnazin 3-rutinoside were identified. Of these, only quercetin and isorhamnetin had already been identified in the leaves of A. geraensis. The results show a fungistatic potential for the species. The diversity of flavonoids present in the leaves of A. geraensis may be the result of a synergistic action between fungus and plant or there could be an antagonistic effect between flavonoids and the other identified chemical classes.

Lipid-lowering, anti-inflammatory, and hepatoprotective effects of isorhamnetin on acetaminophen-induced hepatotoxicity in mice

Isorhamnetin is a hepatoprotective flavonoid molecule derived from the leaves and fruits of Hippophae rhamnoides L. However, the protective effect of isorhamnetin on acetaminophen (APAP) induced hepatotoxicity is still unknown. Thus, we aimed to investigate the lipid-lowering, anti-inflammatory, and hepatoprotective effects of isorhamnetin on APAP-induced hepatotoxicity in mice. Hepatotoxicity was induced by a single injection of APAP (300 mg/kg, intraperitoneally). Isorhamnetin (50 or 100 mg/kg, orally) and N-acetylcysteine (NAC) (200 mg/kg, orally), or vehicle control, were administered 1 h before the administration of APAP. Total antioxidant status (TAS) and total oxidative status (TOS) of liver tissue and levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were analyzed by ELISA. Lipid profiles and liver function parameters were measured using an autoanalyzer. In addition, liver tissue was examined histopathologically. Isorhamnetin treatment significantly reduced the APAP-induced increase in the liver weight and liver index; it also reduced the APAP-induced increase in serum liver parameters (ALT, AST, ALP, and LDH) (p < 0.05). Isorhamnetin significantly reduced APAP-induced oxidative stress and inflammation by increasing TAS levels and decreasing TOS, TNF-α, IL-1β, and IL-6 levels (p < 0.05). Moreover, isorhamnetin treatment significantly regulated lipid profiles (TG, T-C, LDL-C, and HDL-C levels) that changed in response to APAP administration (p < 0.05). In histopathological examination, liver degeneration observed in the APAP group was significantly reduced in the NAC and isorhamnetin-treated groups (p < 0.05). This study suggests that isorhamnetin has a significant protective effect on APAP-induced hepatotoxicity in mice through its lipid-lowering, antioxidant, and anti-inflammatory effects.

Pentoxifylline treats Aspergillus fumigatus keratitis by reducing fungal burden and suppressing corneal inflammation

Fungal keratitis (FK) is a blinding ocular disease, which mainly results from fungal damage and excessive inflammation. Pentoxifylline, a kind of methylxanthine, has been discovered to have anti-inflammatory properties in various infectious diseases, hinting a potential therapeutic effect on treating corneal fungal infection. Whereas, the therapeutic impact of pentoxifylline on fungal keratitis is still uncertain. This study investigated the antifungal capability against Aspergillus fumigatus and the anti-inflammatory role of pentoxifylline by activating nuclear factor, erythroid 2 like 2 (Nrf2)/heme oxygenase1 (HO1) pathway in the process of FK. In our research, we demonstrated that pentoxifylline could effectively inhibit fungal growth and inflammatory reaction. Pentoxifylline reduced the production of pro-inflammatory factors by stimulating the Nrf2/HO1 pathway. Although there was no statistical difference between the curative efficacy of pentoxifylline and natamycin application to FK, pentoxifylline could promote corneal epithelial repair and was less toxicity to the ocular surface than natamycin. In conclusion, pentoxifylline performs antifungal and anti-inflammatory effects by lessening the fungus burden and activating the Nrf2/HO1 pathway, hinting that it has the potential to be a new therapeutic medication for Aspergillus fumigatus keratitis.

Honokiol reduces fungal burden and ameliorate inflammation lesions of Aspergillus fumigatus keratitis via Dectin-2 down-regulation

PURPOSE

To screen and identify the mechanism of honokiol on anti-fungi and anti-inflammation in fungal keratitis (FK) through bioinformatic analysis and biological experiments.

METHODS

Transcriptome profile demonstrated differential expression genes (DEGs) of Aspergillus fumigatus keratitis between PBS-treated and honokiol-treated groups via bioinformatics analyses. Inflammatory substances were quantified by qRT-PCR, Western blot and ELISA, and macrophage polarization was examined by flow cytometry. Periodic acid Schiff staining and morphological interference assay were used to detect hyphal distribution in vivo and fungal germination in vitro, respectively. Electron microscopy was to illustrate hyphal microstructure.

RESULTS

Illumina sequencing demonstrated that compared with the honokiol group, 1175 up-regulated and 383 down-regulated genes were induced in C57BL/6 mice Aspergillus fumigatus keratitis with PBS treatment. Through GO analysis, some differential expression proteins (DEPs) played major roles in biological processes, especially fungal defense and immune activation. KEGG analysis provided fungus-related signaling pathways. PPI analysis demonstrated that DEPs from multiple pathways form a close-knit network, providing a broader context for FK treatment. In biological experiments, Dectin-2, NLRP3 and IL-1β were upregulated by Aspergillus fumigatus to evaluate immune response. Honokiol could reverse the trend, comparable to Dectin-2 siRNA interference. Meanwhile, honokiol could also play an anti-inflammatory role via promoting M2 phenotype polarization. Moreover, honokiol reduced hyphal distribution in the stroma, delayed germination, and destroyed the hyphal cell membrane in-vitro.

CONCLUSIONS

Honokiol possesses anti-fungal and anti-inflammatory effects in Aspergillus fumigatus keratitis and may develop a potential and safe therapeutic modality for FK.

The therapeutic role and mechanism of 4-Methoxycinnamic acid in fungal keratitis

Fungal keratitis is an infectious vision-threatening disease that has a poor prognosis, and the clinical therapeutic drugs have multiple limitations, such as epithelial toxicity and low bioavailability. Therefore, new antifungal treatment strategies must be developed. 4-Methoxycinnamic acid (MCA) is a widely occurring natural phenolic acid that has been proven to have multiple effects, such as antibacterial, antifungal, anti-inflammatory, neuroprotective, and inhibiting cancer. In this research, we explored the effects and underlying mechanisms of MCA on A. fumigatus keratitis and the antifungal effects of the combination of MCA and natamycin (NATA) on A. fumigatus. We found that MCA exerts antifungal effects by inhibiting the synthesis of the fungal cell wall, changing the permeability of fungal cell membranes. Moreover, the MCA-NATA combination exhibited synergy for A. fumigatus. In addition, MCA exerted an anti-inflammatory effect by downregulating the inflammatory factors (IL-1β, TNF-α, IL-6, and iNOS) in C57BL/6 mice and RAW264.7 cells. The anti-inflammatory mechanism of MCA was associated with the Mincle signal pathway. In summary, MCA acts as a potential therapeutic drug for fungal keratitis and a potential antifungal sensitizer for natamycin. MCA inhibits fungal cell wall synthesis, destroys the permeability of fungal cell membranes, and mediates the anti-inflammatory, immune response of the host.

Glabridin Inhibits Aspergillus fumigatus Growth and Alleviate Inflammation Mediated by Dectin-2 and NLRP3 Inflammasome

PURPOSE

The research was used to uncover the mechanism of glabridin in Aspergillus fumigatus keratitis in anti-fungus and anti-inflammation.

METHODS

In vitro, RAW 264.7 cells were infected with A. fumigatus with incubation of glabridin in different concentrations. Real-time quantitative polymerase chain reaction (RT‑qPCR), Western blot, and enzyme-linked immunosorbent assay (ELISA) were used to assess the inflammatory severe and alternation with the intervention of Dectin-2 siRNA and glabridin. In vivo, A. fumigatus keratitis mouse models were established by spore intra-stromal injection and treated with glabridin or PBS. And disease scores, inflammatory mediators, and periodic acid-schiff (PAS) staining were exhibited to demonstrate the therapeutic efficiency of glabridin in vivo. Morphological interference assay monitored fungal germination. Scanning and transmission electron microscopy were used to observe the growth of fungi.

RESULTS

In RAW 264.7 cells and mouse keratitis models, noncytotoxic 16 μg/mL glabridin showed significant inhibition in the expression of Dectin-2, NLRP3, Caspase-1, IL-1β, and TNF-α after A. fumigatus infection, almost similar to the intervention of Dectin-2 siRNA. PAS staining illustrated the reduced hyphal distribution in cornea stroma with glabridin treatment. Glabridin remarkably inhibited A. fumigatus growth through delaying germination and disrupting the integrity of the hyphae membrane.

CONCLUSION

Glabridin plays an anti-inflammatory role in A. fumigatus challenge via suppression of the Dectin-2 and NLRP3 inflammasome, and plays an anti-fungal role through delaying germination and changing the hyphal integrity.KEY MESSAGESGlabridin plays an anti-inflammatory role in A. fumigatus infection of RAW264.7 cells in a concentration-dependent manner and through Dectin-2 mediation.Glabridin decreases fungal distribution and inflammation in mouse A. fumigatus keratitis.Glabridin inhibits A. fumigatus growth by delaying germination and disrupting cellular structure in vitro.

Clinical Evidence and Potential Mechanisms in Treating Radiation Enteritis with Modified Baitouweng Decoction

Objectives

To perform a meta-analysis and network analysis identification to evaluate the efficacy, safety, and potential mechanisms of modified Baitouweng decoction (mBTWD) in the treatment of radiation enteritis.

Methods

We searched PubMed, Embase, Cochrane Library, Web of Science, CNKI, Wanfang Databases, SionMed, and Chinese Scientific Journals Database to collect the randomized controlled trials (RCTs) of mBTWD treating radiation enteritis. Rev.Man 5.3 and Stata 14.0 software are employed for meta-analysis. The GRADE online tool is used to evaluate the quality of evidence. Network analysis and molecular docking approach are applied to predict the potential targets and ingredients of representative drugs in mBTWD for the treatment of radiation enteritis.

Results

Seventeen studies are eventually included, covering a total of 1611 patients: (1) The clinical efficacy is significantly higher in mBTWD groups than in control groups (RR = 1.24, 95% CI (1.17, 1.32), P < 0.00001). (2) mBTWD has certain advantages in improving TCM syndromes (MD = -3.41, P < 0.00001). (3) mBTWD has a certain positive effect on the improvement of intestinal signs and symptoms (RR = 1.23, P=0.0001; OR = 3.51, P < 0.00001). (4) Indexes including CRP, KPS, and OB, are better in mBTWD groups than in control groups (P < 0.00001, P=0.002, P=0.03), but the credibility is downgraded for a small sample size. Adverse events and recurrence rates require further confirmation with larger sample sizes. (5) Univariate meta-regression for clinical efficacy shows none of the coefficients are significantly associated with the estimated risk ratio. The clinical efficacy overestimates about 4.9% from publication bias. The quality of the included studies is low according to GRADE evidence. (6) Quercetin, isorhamnetin, and beta-sitosterol are the main ingredients from representative drugs in mBTWD and its key targets are MYC, TP53, and MAPK14/MAPK1.

Conclusions

mBTWD may be effective in the treatment of radiation enteritis, but its long-term benefits, safety, and molecular mechanisms remain unclear due to the poor quality of the evidence. Larger sample sizes, high-quality studies, and basic research are essential in the future.

Benzyl isothiocyanate improves the prognosis of Aspergillus fumigatus keratitis by reducing fungal load and inhibiting Mincle signal pathway

Aspergillus fumigatus keratitis is a potential blinding disease associated with A. fumigatus invasion and excessive inflammatory response. Benzyl isothiocyanate (BITC) is a secondary metabolite with broad antibacterial and anti-inflammatory activity extracted from cruciferous species. However, the role of BITC in A. fumigatus keratitis has not been discovered yet. This study aims to explore the antifungal and anti-inflammatory effects and mechanisms of BITC in A. fumigatus keratitis. Our results provided evidences that BITC exerted antifungal effects against A. fumigatus by damaging cell membranes, mitochondria, adhesion, and biofilms in a concentration-dependent manner. In vivo, fungal load and inflammatory response including inflammatory cell infiltration and pro-inflammatory cytokine expression were reduced in BITC-treated A. fumigatus keratitis. Additionally, BITC significantly decreased Mincle, IL-1β, TNF-α, and IL-6 expression in RAW264.7 cells that stimulated by A. fumigatus or Mincle ligand trehalose-6,6-dibehenate. In summary, BITC possessed fungicidal activities and could improve the prognosis of A. fumigatus keratitis by reducing fungal load and inhibiting the inflammatory response mediated by Mincle.

A Novel Monoclonal Antibody 1D2 That Broadly Inhibits Clinically Important Aspergillus Species

Aspergillus fumigatus is a ubiquitous airborne fungus, is the predominant cause (>90%) of invasive aspergillosis (IA) in immunosuppressed patients and has a high mortality. New approaches to prevention and treatment are needed because of the poor efficacy, toxicity and side effects of the current anti-Aspergillus drugs on patients. Thus, we aim to explore a new avenue to combat Aspergillus infection by using a novel monoclonal antibody (mAb) 1D2 against a glycoprotein on the cell wall of Aspergillus. The ability of this mAb to inhibit attachment, germination, and growth of Aspergillus conidia and hyphae in vitro were examined. A dose-dependent growth inhibition of Aspergillus conidia in the presence of mAb 1D2 was found. The mAb 1D2 inhibited attachment of Aspergillus conidia to an untreated slide surface and fibronectin-treated surface compared to an unrelated mAb 6B10. When conidia were exposed to 1D2 concomitantly with inoculation into culture media, the mAb prevented the swelling and germination of conidia. This inhibitory ability of 1D2 was less apparent if it was added two hours after inoculation. Damage to hyphae was also observed when 1D2 was added to Aspergillus hyphae that had been incubated in media overnight. These in vitro results indicate that mAb 1D2 broadly inhibits clinically important Aspergillus species and has a promising therapeutic effect both as prophylaxis to inhibit an Aspergillus infection as well as a treatment.

Oxidized chondroitin sulfate eye drops ameliorate the prognosis of fungal keratitis with anti-inflammatory and antifungal effects

Fungal keratitis (FK) is a refractory ophthalmic disease that can result in vision impairment and even blindness due to the severe fungal invasiveness and excessive inflammatory response. Therefore, antifungal treatment combined with local immunosuppressive therapy is regarded as the most effective strategy to improve the clinical outcome of FK. Oxidized polysaccharides with aldehyde groups possess obvious inhibitory activity towards microorganisms. Herein, we use chondroitin sulfate (CS), a recognized anti-inflammatory biopolysaccharide, to prepare oxidized chondroitin sulfate (OCS) via sodium periodate (NaIO₄) oxidation for the treatment of FK. The chemical structure of OCS was characterized by FTIR, ¹H NMR, and XPS, revealing that the O-dihydroxy in the D-glucuronic acid unit of CS was selectively broken by NaIO₄, forming active aldehyde groups. The introduction of aldehydes not only retains the anti-inflammatory activity but also confers OCS with antifungal property. In vitro antifungal experiments showed that OCS inhibits the growth, represses the biofilm formation and alters the membrane integrity of A. fumigatus. The toxicity of OCS was evaluated by cytotoxicity tests (CCK-8) and the Draize eye test in vitro and in vivo. qRT-PCR confirmed that OCS had similar anti-inflammatory activity as CS. In mice with A. fumigatus keratitis, OCS versus CS or PBS showed an excellent therapeutic effect, characterized by a lower corneal inflammation score, less fungal load, reduced neutrophil recruitment, and the downregulated expression of pro-inflammatory factors. Our findings demonstrate that OCS improves the prognosis of A. fumigatus keratitis in mice by inhibiting the growth of fungi, reducing the recruitment of neutrophils and inhibiting the inflammatory response. It provides innovative ideas for the development and application of OCS in medicine and biomaterials fields.

Exploring the Mechanism of Hawthorn Leaves Against Coronary Heart Disease Using Network Pharmacology and Molecular Docking

Hawthorn leaves, which is a traditional Chinese medicine (TCM), has been used for treating coronary heart disease (CHD) for a long time in China. But the limited understanding of the main active components and molecular mechanisms of this traditional medicine has restricted its application and further research. The active compounds of hawthorn leaves were obtained from TCMSP database and SymMap database. The targets of it were predicted based on TCMSP, PubChem, Swiss Target Prediction, and SymMap database. The putative targets of CHD were gathered from multi-sources databases including the Online Mendelian Inheritance in Man (OMIM) database, the DrugBank database, the GeneCards database and the DisGeNet database. Network topology analysis, GO and KEGG pathway enrichment analyses were performed to select the key targets and pathways. Molecular docking was performed to demonstrate the binding capacity of the key compounds to the predicted targets. Furthermore, RAW264.7 cells stimulated by lipopolysaccharides (LPS) were treated with three effective compounds of hawthorn leaves to assess reliability of prediction. Quercetin, isorhamnetin and kaempferol were main active compounds in hawthorn leaves. Forty four candidate therapeutic targets were identified to be involved in protection of hawthorn leaves against CHD. Additionally, the effective compounds of it had good binding affinities to PTGS2, EGFR, and MMP2. Enrichment analyses suggested that immune inflammation related biological processes and pathways were possibly the potential mechanism. Besides, we found that three predicted effective compounds of hawthorn leaves decreased protein expression of PTGS2, MMP2, MMP9, IL6, IL1B, TNFα and inhibited activation of macrophage. In summary, the present study demonstrates that quercetin, kaempferol and isorhamnetin are proved to be the main effective compounds of hawthorn leaves in treatment of CHD, possibly by suppressing expression of PTGS2, MMP2, MMP9, inflammatory cytokines and macrophages viability. This study provides a new understanding of the active components and mechanisms of hawthorn leaves treating CHD from the perspective of network pharmacology.

Perillaldehyde protects against Aspergillus fumigatus keratitis by reducing fungal load and inhibiting inflammatory cytokines and LOX-1

PURPOSE

The purpose of this research was to explore the antifungal and anti-inflammatory effects of perillaldehyde (PAE) in Aspergillus fumigatus (A.fumigatus) keratitis and the underlying mechanism.

METHODS

The biofilm formation, adherence assay, propidium iodide uptake test were used to determine the possible mechanism of PAE in terms of antifungal effects in vitro. The severity of corneal infection was evaluated by clinical scores. The immunofluorescence staining was adopt to detect the number of macrophages in infected corneas. Draize test was performed to assess the ocular toxicity of PAE. Real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and Western blot reflected the expression of inflammatory cytokines and Lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) in mice corneas and RAW264.7 cells.

RESULTS

PAE was able to inhibit the formation of biofilm, reduce conidial adhesion, and damage the integrity of membranes to exert antifungal activity. In C57BL/6 mice models, PAE alleviated the severity of infected corneas, reduced the recruitment of macrophages and had low ocular toxicity. In addition, the mRNA and protein levels of TNF-α, CCL-2 and LOX-1 could be significantly decreased by the application of PAE after A.fumigatus infection in vivo and in vitro.

CONCLUSION

Our study indicated that PAE protected against A.fumigatus keratitis by reducing fungal load, accumulation of macrophages, and inhibiting the expression of inflammatory cytokines.

Efficacy of Duhuo Jisheng Decoction in Treating Ankylosing Spondylitis: Clinical Evidence and Potential Mechanisms

Background

Duhuo Jisheng Decoction (DHJSD) is an ancient compound widely used in the treatment of ankylosing spondylitis (AS). However, its efficacy is controversial, and its mechanism of action is not clear enough. Using meta-analysis and network pharmacology, our study evaluated the clinical efficacy of DHJSD in the treatment of AS and explored its mechanisms of action.

Methods

We searched medical databases, including Embase, PubMed, the China National Knowledge Infrastructure databases, Wanfang, and the Chinese Scientific Journal Database, to identify studies that met the inclusion criteria. RevMan 5.3 software was used for the meta-analysis. The compounds and the potential protein targets of DHJSD were obtained from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database and analysis platform. AS was treated as a search query in the NCBI, PharmGKB, TTD, DrugBank, and OMIM databases to obtain disease-related genes. The overlapping targets of DHJSD and AS were identified, and then Gene Ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed. Cytoscape was employed to construct a drug-compound-target network and a protein-protein interaction (PPI) network. CytoHubba was utilized to select the hub genes.

Results

A total of 10 studies involving 860 participants were included in the meta-analysis. Compared with the control, DHJSD treatment significantly improved clinical symptoms; reduced the erythrocyte sedimentation rate (ESR), the C-reactive protein (CPR), and interleukin 6 (IL-6) levels; increased the degree of motion of the chest; reduced the visual analog scale (VAS) pain score; reduced Schober's test values; reduced the finger-to-floor distance; reduced the duration of morning stiffness. However, the differences were not statistically significant in the Bath Ankylosing Spondylitis Functional Index scores, the Bath Ankylosing Spondylitis Disease Activity Index scores, the bone Gla-containing protein (BGP) levels, or the bone alkaline phosphatase (BALP) levels. In terms of adverse events, DHJSD treatment of AS reduced the incidence of gastrointestinal events, the incidence of skin events, and the incidence of abnormal liver function; however, there was no statistically significant reduction in the incidence of adverse renal function events. Subgroup analysis showed that in the treatment of AS, the clinical effect of DHJSD for AS was better than that of the controls for both treatment durations, ≤2 months and >2 months. A total of 178 active compounds and 47 related potential targets were identified for DHJSD in the treatment of AS, including four hub genes (CXCL8, PTGS2, VEGFA, and STAT3). The core active ingredients of DHJSD in the treatment of AS were mainly quercetin, kaempferol, licochalcone A, and isorhamnetin. DHJSD treatment of AS-related pathways mainly involved the IL-17 signaling pathway, the TNF signaling pathway, and the rheumatoid arthritis signaling pathway.

Conclusion

The above results suggest that DHJSD acts on AS through multiple targets, components, and pathways with significant clinical efficacy. Future studies may further explore the active components of DHJSD.

Preparation of a Nanobody Specific to Dectin 1 and Its Anti-inflammatory Effects on Fungal Keratitis

Objective

To prepare a nanobody specific to dectin 1 and verify its specificity and anti-inflammatory effects on Aspergillus fumigatus keratitis.

Methods

The nanobody was selected from a high-quality shark-antibody library constructed with phage-display technology. The nanobody was developed in the expression systems of Escherichia coli. Indirect ELISA was used to determine the specificity of the nanobody to recombinant dectin 1 protein. The potential of the nanobody to be recognized and expressed on the surfaces of cells and corneas was detected by immunofluorescence, and its anti-inflammatory effect on A. fumigatus keratitis was further verified. After infection with A. fumigatus, eyes of C57B L/6 mice were treated with nanobodies. Human corneal epithelial cells (HCECs) were pretreated with nanobodies and then incubated with A. fumigatus. Clinical scores and slit-lamp photography were used to assess disease response in mouse corneas. RT-PCR and ELISA were used to evaluate mRNA and protein expression of IL1β and IL6 in both mouse corneas and HCECs.

Results

The nanobody was successfully expressed through microbial system and showed specific high-affinity binding to recombinant dectin 1. Furthermore, it exhibited specific binding to dectin 1 expressed on the surfaces of cells and recognized dectin 1 in mouse corneas. Importantly, it reduced clinical scores of A. fumigatus keratitis in mice compared with a PBS-treatment group. In addition, it decreased mRNA and protein expression of IL1β and IL6 in infected corneas and HCECs stimulated with A. fumigatus.

Conclusion

These results suggest that this nanobody can bring about anti-inflammatory effects. This highlights the potential of these nanobodies as innovative therapeutic agents in A. fumigatus.