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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-1ß 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.
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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-1ß 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-1ß, IL-6, etc. expression and play protective effect on corneal nerves.
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Antiinflamatorios , Aspergillus fumigatus , Queratitis , Lectinas Tipo C , Fármacos Neuroprotectores , Resveratrol , Proteínas Quinasas p38 Activadas por Mitógenos , Aspergillus fumigatus/efectos de los fármacos , Lectinas Tipo C/metabolismo , Queratitis/tratamiento farmacológico , Queratitis/metabolismo , Queratitis/microbiología , Resveratrol/farmacología , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Animales , Fármacos Neuroprotectores/farmacología , Antiinflamatorios/farmacología , Ratones , Aspergilosis/tratamiento farmacológico , Aspergilosis/metabolismo , Antifúngicos/farmacología , Masculino , Transducción de Señal/efectos de los fármacos , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Córnea/efectos de los fármacos , Córnea/metabolismoRESUMEN
Fluid elements deform in turbulence by stretching and folding. In this Letter, by projecting the material deformation tensor onto the largest stretching direction, we depict the dynamics of folding through the evolution of the material curvature. Results from direct numerical simulation (DNS) show that the curvature growth exhibits two regimes: first, a linear stage dominated by folding fluid elements through a persistent velocity Hessian that then transition to an exponential-growth stage driven by the stretching of already strongly bent fluid elements. This transition leads to strong curvature intermittency at later stages, which can be explained by a proposed curvature-evolution model. The link between velocity Hessian to folding provides a new way to understand the crucial steps in energy cascade and mixing in turbulence beyond the classical linear description of stretching dynamics.
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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.
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Aspergilosis , Infecciones Fúngicas del Ojo , Queratitis , Pentoxifilina , Humanos , Animales , Ratones , Aspergillus fumigatus , Natamicina/uso terapéutico , Pentoxifilina/farmacología , Pentoxifilina/uso terapéutico , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Factor 2 Relacionado con NF-E2 , Aspergilosis/tratamiento farmacológico , Aspergilosis/metabolismo , Queratitis/metabolismo , Inflamación/tratamiento farmacológico , Infecciones Fúngicas del Ojo/tratamiento farmacológico , Antiinflamatorios/farmacología , Antiinflamatorios/uso terapéutico , Ratones Endogámicos C57BLRESUMEN
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-1ß, 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.
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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-1ß, 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.
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Aspergilosis , Infecciones Fúngicas del Ojo , Queratitis , Animales , Ratones , Natamicina/farmacología , Natamicina/uso terapéutico , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Aspergillus fumigatus , Ratones Endogámicos C57BL , Infecciones Fúngicas del Ojo/tratamiento farmacológicoRESUMEN
From air-sea gas exchange, oil pollution, to bioreactors, the ubiquitous fragmentation of bubbles/drops in turbulence has been modeled by relying on the classical Kolmogorov-Hinze paradigm since the 1950s. This framework hypothesizes that bubbles/drops are broken solely by eddies of the same size, even though turbulence is well known for its wide spectrum of scales. Here, by designing an experiment that can physically and cleanly disentangle eddies of various sizes, we report the experimental evidence to challenge this hypothesis and show that bubbles are preferentially broken by the sub-bubble-scale eddies. Our work also highlights that fragmentation cannot be quantified solely by the stress criterion or the Weber number; The competition between different time scales is equally important. Instead of being elongated slowly and persistently by flows at their own scales, bubbles are fragmented in turbulence by small eddies via a burst of intense local deformation within a short time.