HSP90 Modulates T2R Bitter Taste Receptor Nitric Oxide Production and Innate Immune Responses in Human Airway Epithelial Cells and Macrophages

How effective is topical miconazole or amorolfine for mild to moderately severe onychomycosis in primary care: the Onycho Trial - a randomised double-blind placebo-controlled trial

OBJECTIVES

To evaluate the efficacy of topical miconazole or amorolfine compared to placebo for mild to moderately severe onychomycosis.

DESIGN

Randomised, double-blind, placebo-controlled trial, with computer-generated treatment allocation at a 1:1:1 ratio.

SETTING

Primary care, recruitment from February 2020 to August 2022.

PARTICIPANTS

193 patients with suspected mild to moderately severe onychomycosis were recruited via general practices and from the general public, 111 of whom met the study criteria. The mean age of participants was 51 (SD 13.1), 51% were female and onychomycosis was moderately severe (mean OSI 12.1 (SD 8.0)).

INTERVENTIONS

Once-daily miconazole 20 mg/g or once-weekly amorolfine 5% nail lacquer solution was compared with placebo (denatonium benzoate solution).

MAIN OUTCOME MEASURES

Complete, clinical and mycological cure at 6 months. Secondary outcomes were clinical improvement, symptom burden, quality of life, adverse effects, compliance, patient-perceived improvement and treatment acceptability.

RESULTS

Based on intention-to-treat analysis, none of the participants receiving miconazole or amorolfine reached complete cure compared with two in the placebo group (OR not estimable (n.e.), p=0.493 and OR n.e., p=0.240, respectively). There was no evidence of a significant difference between groups regarding clinical cure (OR n.e., p=0.493 and OR 0.47, 95% CI 0.04 to 5.45, p=0.615) while miconazole and amorolfine were less effective than placebo at reaching both mycological cure (OR 0.25, 95% CI 0.06 to 0.98, p=0.037 and OR 0.23, 95% CI 0.06 to 0.92, p=0.029, respectively) and clinical improvement (OR 0.26, 95% CI 0.08 to 0.91, p=0.028 and OR 0.25, 95% CI 0.07 to 0.85, p=0.021, respectively). There was no evidence of a significant difference in disease burden, quality of life, adverse reactions, compliance, patient-perceived improvement or treatment acceptability.

CONCLUSIONS

Topical miconazole and amorolfine were not effective in achieving a complete, clinical or mycological cure of mild to moderately severe onychomycosis, nor did they significantly alleviate the severity or symptom burden. These treatments should, therefore, not be advised as monotherapy to treat onychomycosis.

TRIAL REGISTRATION NUMBER

WHO ICTRP NL8193.

GPRC5A promotes paclitaxel resistance and glucose content in NSCLC

Lung cancer is one of the most common and malignant cancers worldwide. Chemotherapy has been widely used in the clinical setting, and paclitaxel is the first-line therapy for lung cancer patients but paclitaxel resistance is the main problem. First, we successfully established paclitaxel-resistant lung cancer cells treated with elevated doses of paclitaxel for 3 months, as confirmed by the CCK-8 assay. Paclitaxel-resistant cancer cells increased glucose content. Second, Gtex, Oncomine, and gene expression omnibus database data mining identified GPRC5A, G protein-coupled receptor, as the most prominent differentially expressed gene in drug-resistant datasets including gemcitabine, paclitaxel, and gefitinib overlapped with the microarray data from cancer cell metabolism. Third, qPCR analysis and western blot technique showed that GPRC5A mRNA and protein levels were significantly enhanced in paclitaxel-resistant lung cancer cells. Fourth, functional analysis was conducted by siRNA-mediated transient knockdown of GPRC5A. Silencing GPRC5A significantly decreased paclitaxel resistance and glucose content. In the end, retinoic acid substantially upregulated GPRC5A proteins and promoted glucose content in two lung cancer cells. Kaplan-Meier plot also confirmed that lung cancer patients with high expression of GPRC5A had a relatively lower survival rate. Our study provided a potential drug target GPRC5A, which may benefit lung cancer patients with acquired paclitaxel resistance in the future and a theoretical basis for future preclinical trials.

In vitro modelling of bacterial pneumonia: a comparative analysis of widely applied complex cell culture models

Bacterial pneumonia greatly contributes to the disease burden and mortality of lower respiratory tract infections among all age groups and risk profiles. Therefore, laboratory modelling of bacterial pneumonia remains important for elucidating the complex host-pathogen interactions and to determine drug efficacy and toxicity. In vitro cell culture enables for the creation of high-throughput, specific disease models in a tightly controlled environment. Advanced human cell culture models specifically, can bridge the research gap between the classical two-dimensional cell models and animal models. This review provides an overview of the current status of the development of complex cellular in vitro models to study bacterial pneumonia infections, with a focus on air-liquid interface models, spheroid, organoid, and lung-on-a-chip models. For the wide scale, comparative literature search, we selected six clinically highly relevant bacteria (Pseudomonas aeruginosa, Mycoplasma pneumoniae, Haemophilus influenzae, Mycobacterium tuberculosis, Streptococcus pneumoniae, and Staphylococcus aureus). We reviewed the cell lines that are commonly used, as well as trends and discrepancies in the methodology, ranging from cell infection parameters to assay read-outs. We also highlighted the importance of model validation and data transparency in guiding the research field towards more complex infection models.

Akt activator SC79 stimulates antibacterial nitric oxide generation in human nasal epithelial cells in vitro

BACKGROUND

The role of Akt in nasal immunity is unstudied. Akt phosphorylates and activates endothelial nitric oxide synthase (eNOS) expressed in epithelial ciliated cells. Nitric oxide (NO) production by ciliated cells can have antibacterial and antiviral effects. Increasing nasal NO may be a useful antipathogen strategy in chronic rhinosinusitis (CRS). We previously showed that small-molecule Akt activator SC79 induces nasal cell NO production and suppresses IL-8 via the transcription factor Nrf-2. We hypothesized that SC79 NO production may additionally have antibacterial effects.

METHODS

NO production was measured using fluorescent dye DAF-FM. We tested effects of SC79 during co-culture of Pseudomonas aeruginosa with primary nasal epithelial cells, using CFU counting and live-dead staining to quantify bacterial killing. Pharmacology determined the mechanism of SC79-induced NO production and tested dependence on Akt.

RESULTS

SC79 induced dose-dependent, Akt-dependent NO production in nasal epithelial cells. The NO production required eNOS and Akt. The NO released into the airway surface liquid killed P. aeruginosa. No toxicity (LDH release) or inflammatory effects (IL8 transcription) were observed over 24 h.

CONCLUSIONS

Together, these data suggest multiple immune pathways are stimulated by SC79, with antipathogen effects. This in vitro pilot study suggests that a small-molecule Akt activator may have clinical utility in CRS or respiratory other infection settings, warranting future in vivo studies.

Global warming and implications for epithelial barrier disruption and respiratory and dermatologic allergic diseases

Global warming has direct and indirect effects, as well as short- and long-term impacts on the respiratory and skin barriers. Extreme temperature directly affects the airway epithelial barrier by disrupting the structural proteins and by triggering airway inflammation and hyperreactivity. It enhances tidal volume and respiratory rate by affecting the thermoregulatory system, causing specific airway resistance and reflex bronchoconstriction via activation of bronchopulmonary vagal C fibers and upregulation of transient receptor potential vanilloid (TRPV) 1 and TRPV4. Heat shock proteins are activated under heat stress and contribute to both epithelial barrier dysfunction and airway inflammation. Accordingly, the frequency and severity of allergic rhinitis and asthma have been increasing. Heat activates TRPV3 in keratinocytes, causing the secretion of inflammatory mediators and eventually pruritus. Exposure to air pollutants alters the expression of genes that control skin barrier integrity and triggers an immune response, increasing the incidence and prevalence of atopic dermatitis. There is evidence that extreme temperature, heavy rains and floods, air pollution, and wildfires increase atopic dermatitis flares. In this narrative review, focused on the last 3 years of literature, we explore the effects of global warming on respiratory and skin barrier and their clinical consequences.

Cellular mechanisms and molecular pathways linking bitter taste receptor signalling to cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction in heart diseases

Heart diseases and related complications constitute a leading cause of death and socioeconomic threat worldwide. Despite intense efforts and research on the pathogenetic mechanisms of these diseases, the underlying cellular and molecular mechanisms are yet to be completely understood. Several lines of evidence indicate a critical role of inflammatory and oxidative stress responses in the development and progression of heart diseases. Nevertheless, the molecular machinery that drives cardiac inflammation and oxidative stress is not completely known. Recent data suggest an important role of cardiac bitter taste receptors (TAS2Rs) in the pathogenetic mechanism of heart diseases. Independent groups of researchers have demonstrated a central role of TAS2Rs in mediating inflammatory, oxidative stress responses, autophagy, impulse generation/propagation and contractile activities in the heart, suggesting that dysfunctional TAS2R signalling may predispose to cardiac inflammatory and oxidative stress disorders, characterised by contractile dysfunction and arrhythmia. Moreover, cardiac TAS2Rs act as gateway surveillance units that monitor and detect toxigenic or pathogenic molecules, including microbial components, and initiate responses that ultimately culminate in protection of the host against the aggression. Unfortunately, however, the molecular mechanisms that link TAS2R sensing of the cardiac milieu to inflammatory and oxidative stress responses are not clearly known. Therefore, we sought to review the possible role of TAS2R signalling in the pathophysiology of cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction in heart diseases. Potential therapeutic significance of targeting TAS2R or its downstream signalling molecules in cardiac inflammation, oxidative stress, arrhythmia and contractile dysfunction is also discussed.

Loss of CFTR function is associated with reduced bitter taste receptor-stimulated nitric oxide innate immune responses in nasal epithelial cells and macrophages

Introduction

Bitter taste receptors (T2Rs) are G protein-coupled receptors identified on the tongue but expressed all over the body, including in airway cilia and macrophages, where T2Rs serve an immune role. T2R isoforms detect bitter metabolites (quinolones and acyl-homoserine lactones) secreted by gram negative bacteria, including Pseudomonas aeruginosa, a major pathogen in cystic fibrosis (CF). T2R activation by bitter bacterial products triggers calcium-dependent nitric oxide (NO) production. In airway cells, the NO increases mucociliary clearance and has direct antibacterial properties. In macrophages, the same pathway enhances phagocytosis. Because prior studies linked CF with reduced NO, we hypothesized that CF cells may have reduced T2R/NO responses, possibly contributing to reduced innate immunity in CF.

Methods

Immunofluorescence, qPCR, and live cell imaging were used to measure T2R localization, calcium and NO signaling, ciliary beating, and antimicrobial responses in air-liquid interface cultures of primary human nasal epithelial cells and immortalized bronchial cell lines. Immunofluorescence and live cell imaging was used to measure T2R signaling and phagocytosis in primary human monocyte-derived macrophages.

Results

Primary nasal epithelial cells from both CF and non-CF patients exhibited similar T2R expression, localization, and calcium signals. However, CF cells exhibited reduced NO production also observed in immortalized CFBE41o- CF cells and non-CF 16HBE cells CRISPR modified with CF-causing mutations in the CF transmembrane conductance regulator (CFTR). NO was restored by VX-770/VX-809 corrector/potentiator pre-treatment, suggesting reduced NO in CF cells is due to loss of CFTR function. In nasal cells, reduced NO correlated with reduced ciliary and antibacterial responses. In primary human macrophages, inhibition of CFTR reduced NO production and phagocytosis during T2R stimulation.

Conclusions

Together, these data suggest an intrinsic deficiency in T2R/NO signaling caused by loss of CFTR function that may contribute to intrinsic susceptibilities of CF patients to P. aeruginosa and other gram-negative bacteria that activate T2Rs.

The Complex Journey of the Calcium Regulation Downstream of TAS2R Activation

Bitter taste receptors (TAS2Rs) have recently arisen as a potential drug target for asthma due to their localization in airway cells. These receptors are expressed in all cell types of the respiratory system comprising epithelial, smooth muscle and immune cells; however, the expression pattern of the subtypes is different in each cell type and, accordingly, so is their role, for example, anti-inflammatory or bronchodilator. The most challenging aspect in studying TAS2Rs has been the identification of the downstream signaling cascades. Indeed, TAS2R activation leads to canonical IP3-dependent calcium release from the ER, but, alongside, there are other mechanisms that differ according to the histological localization. In this review, we summarize the current knowledge on the cytosolic calcium modulation downstream of TAS2R activation in the epithelial, smooth muscle and immune cells of the airway system.