Dual inhibition of airway inflammation and fibrosis by common ß cytokine receptor blockade.

BACKGROUND: Patients with severe asthma can present with eosinophilic type 2 (T2), neutrophilic, or mixed inflammation that drives airway remodeling and exacerbations and represents a major treatment challenge. The common ß (ßc) receptor signals for 3 cytokines, GM-CSF, IL-5, and IL-3, which collectively mediate T2 and neutrophilic inflammation. OBJECTIVE: To determine the pathogenesis of ßc receptor-mediated inflammation and remodeling in severe asthma and to investigate ßc antagonism as a therapeutic strategy for mixed granulocytic airway disease. METHODS: ßc gene expression was analyzed in bronchial biopsy specimens from patients with mild-to-moderate and severe asthma. House dust mite extract and Aspergillus fumigatus extract (ASP) models were used to establish asthma-like pathology and airway remodeling in human ßc transgenic mice. Lung tissue gene expression was analyzed by RNA sequencing. The mAb CSL311 targeting the shared cytokine binding site of ßc was used to block ßc signaling. RESULTS: ßc gene expression was increased in patients with severe asthma. CSL311 potently reduced lung neutrophils, eosinophils, and interstitial macrophages and improved airway pathology and lung function in the acute steroid-resistant house dust mite extract model. Chronic intranasal ASP exposure induced airway inflammation and fibrosis and impaired lung function that was inhibited by CSL311. CSL311 normalized the ASP-induced fibrosis-associated extracellular matrix gene expression network and strongly reduced signatures of cellular inflammation in the lung. CONCLUSIONS: ßc cytokines drive steroid-resistant mixed myeloid cell airway inflammation and fibrosis. The anti-ßc antibody CSL311 effectively inhibits mixed T2/neutrophilic inflammation and severe asthma-like pathology and reverses fibrosis gene signatures induced by exposure to commonly encountered environmental allergens.

IgE receptor of mast cells signals mediator release and inflammation via adaptor protein 14-3-3ζ.

BACKGROUND: Mast cells (MCs) are tissue-resident immune cells that mediate IgE-dependent allergic responses. Downstream of FcεRI, an intricate network of receptor-specific signaling pathways and adaptor proteins govern MC function. The 14-3-3 family of serine-threonine phosphorylation-dependent adapter proteins are known to organize intracellular signaling. However, the role of 14-3-3 in IgE-dependent activation remains poorly defined. OBJECTIVE: We sought to determine whether 14-3-3 proteins are required for IgE-dependent MC activation and whether 14-3-3 is a viable target for the treatment of MC-mediated inflammatory diseases. METHODS: Genetic manipulation of 14-3-3ζ expression in human and mouse MCs was performed and IgE-dependent mediator release assessed. Pharmacologic inhibitors of 14-3-3 and 14-3-3ζ knockout mice were used to assess 14-3-3ζ function in a MC-dependent in vivo passive cutaneous anaphylaxis (PCA) model of allergic inflammation. Expression and function of 14-3-3ζ were assessed in human nasal polyp tissue MCs. RESULTS: IgE-dependent mediator release from human MCs was decreased by 14-3-3ζ knockdown and increased by 14-3-3ζ overexpression. Deletion of the 14-3-3ζ gene decreased IgE-dependent activation of mouse MCs in vitro and PCA responses in vivo. Furthermore, the 14-3-3 inhibitor, RB-11, which impairs dimerization of 14-3-3, inhibited cultured MC and polyp tissue MC activation and signaling downstream of the FcεRI receptor and dose-dependently attenuated PCA responses. CONCLUSION: IgE/FcεRI-mediated MC activation is positively regulated by 14-3-3ζ. We identify a critical role for this p-Ser/Thr-binding protein in the regulation of MC FcεRI signaling and IgE-dependent immune responses and show that this pathway may be amenable to pharmacologic targeting.

Liquid Crystal Nanoparticles Enhance Tobramycin Efficacy in a Murine Model of Pseudomonas aeruginosa Biofilm Wound Infection.

Chronic Pseudomonas aeruginosa wound infections are highly prevalent and often untreatable due to biofilm formation, resulting in high antimicrobial tolerance. Standard antibiotic therapy for P. aeruginosa infections involves tobramycin, yet it is highly ineffective as monotherapy as tobramycin cannot penetrate the biofilm to elicit its antimicrobial effect. Lipid liquid crystal nanoparticles (LCNPs) have previously been shown to increase the antimicrobial efficacy and penetration of tobramycin against P. aeruginosa biofilms in vitro and ex vivo. Here, for the first time, we have developed a chronic P. aeruginosa biofilm infection in full-thickness wounds in mice to examine the potential of LCNPs to improve the effect of tobramycin, preclinically. After three doses, administered once a day, tobramycin-LCNPs significantly reduced the P. aeruginosa bacterial load in murine wounds 1000-fold more than unformulated tobramycin, which in turn showed no significant difference to the saline control treatment. Consistent with the improved P. aeruginosa eradication, the tobramycin-LCNPs promoted wound healing. In comparison to previous in vitro and ex vivo data, we show a strong in vitro-in vivo correlation between P. aeruginosa biofilm infection models. The enhanced activity of tobramycin-LCNPs in vivo in the preclinical murine model demonstrates the strong potential of LCNPs as a next-generation formulation approach to improve the efficacy of tobramycin against P. aeruginosa biofilm wound infections.

Liquid crystal nanoparticle platform for increased efficacy of cationic antimicrobials against biofilm infections.

Bacterial biofilm infections tolerate high concentrations of antibiotics and are insidiously challenging to treat. Liquid crystal nanoparticles (LCNPs) advance the efficacy of tobramycin in biofilm-related infections by increasing the penetration of antibiotics across the biofilm matrix. Herewith, we develop the LCNPs as a platform technology, demonstrating that the LCNPs can increase the efficacy of two antibiotic classes (i.e. aminoglycosides and colistin) in P. aeruginosa biofilm infections. In C. elegans, the LCNPs potentiated the antimicrobial effect and significantly improved the survival of the nematodes. In mice with a full-thickness excisional wound, LCNPs were non-toxic and did not impair wound repair. Compared to the unformulated antibiotic treatment, tobramycin-LCNPs reduced the chronic bacterial load by 100-fold in the wound. This was also emulated in an ex vivo P. aeruginosa porcine wound infection model. The LCNPs represent a versatile platform technology that improves the efficacy of cationic antibiotics against biofilm infections utilizing multiple administration routes.

Enzyme responsive copolymer micelles enhance the anti-biofilm efficacy of the antiseptic chlorhexidine.

Staphylococcal biofilms cause many infectious diseases and are highly tolerant to the effects of antimicrobials; this is partly due to the biofilm matrix, which acts as a physical barrier retarding the penetration and reducing susceptibility to antimicrobials, thereby decreasing successful treatment outcomes. In this study, both single and mixed micellar systems based on poly vinyl caprolactam (PCL)-polyethylene glycol (PEG) copolymers were optimised for delivery of chlorhexidine (CHX) to S. aureus, MRSA and S. epidermidis biofilms and evaluated for their toxicity using Caenorhabditis elegans. The respective polyethylene glycol (PEG) and poly vinyl caprolactam (PCL) structural components promoted stealth properties and enzymatic responsive release of CHX inside biofilms, leading to significantly enhanced penetration (56%) compared with free CHX and improving the efficacy against Staphylococcus aureus biofilms grown on an artificial dermis (2.4 log reduction of CFU). Mixing Soluplus-based micelles with Solutol further enhanced the CHX penetration (71%) and promoted maximum reduction in biofilm biomass (>60%). Nematodes-based toxicity assay showed micelles with no lethal effects as indicated by their high survival rate (100%) after 72 h exposure. This study thus demonstrated that bio-responsive carriers can be designed to deliver a poorly water-soluble antimicrobial agent and advance the control of biofilm associated infections.

Marking nut anaphylaxis.

Marking nut Semecarpus anacardium, so-called because it contains a pigment that has been used in the past to mark fabrics, is a known cause of contact hypersensitivity. It may be ingested as an ingredient of some traditional Hindi foods. We describe the first reported case of anaphylaxis to marking nut.