Novel and emerging therapies for asthma

RNA-sequencing and mass-spectrometry proteomic time-series analysis of T-cell differentiation identified multiple splice variants models that predicted validated protein biomarkers in inflammatory diseases

Profiling of mRNA expression is an important method to identify biomarkers but complicated by limited correlations between mRNA expression and protein abundance. We hypothesised that these correlations could be improved by mathematical models based on measuring splice variants and time delay in protein translation. We characterised time-series of primary human naïve CD4+ T cells during early T helper type 1 differentiation with RNA-sequencing and mass-spectrometry proteomics. We performed computational time-series analysis in this system and in two other key human and murine immune cell types. Linear mathematical mixed time delayed splice variant models were used to predict protein abundances, and the models were validated using out-of-sample predictions. Lastly, we re-analysed RNA-seq datasets to evaluate biomarker discovery in five T-cell associated diseases, further validating the findings for multiple sclerosis (MS) and asthma. The new models significantly out-performing models not including the usage of multiple splice variants and time delays, as shown in cross-validation tests. Our mathematical models provided more differentially expressed proteins between patients and controls in all five diseases. Moreover, analysis of these proteins in asthma and MS supported their relevance. One marker, sCD27, was validated in MS using two independent cohorts for evaluating response to treatment and disease prognosis. In summary, our splice variant and time delay models substantially improved the prediction of protein abundance from mRNA expression in three different immune cell types. The models provided valuable biomarker candidates, which were further validated in MS and asthma.

[Diagnosis and treatment guidelines for difficult-to-control asthma in children]

Children suffering from difficult-to-control asthma (DCA) require frequent appointments with their physician, complex treatment regimes and often admissions to hospital. Less than 5% of the asthmatic population suffer this condition. DCA must be correctly characterised to rule out false causes of DCA and requires making a differential diagnosis from pathologies that mimic asthma, comorbidity, environmental and psychological factors, and analysing the factors to determine poor treatment compliance. In true DCA cases, inflammation studies (exhaled nitric oxide, induced sputum, broncho-alveolar lavage and bronchial biopsy), pulmonary function and other clinical aspects can classify DCA into different phenotypes which could make therapeutic decision-making easier.

Proinflammatory and Th2 cytokines regulate the high affinity IgE receptor (FcepsilonRI) and IgE-dependant activation of human airway smooth muscle cells

Background

The high affinity IgE receptor (FcεRI) is a crucial structure for IgE-mediated allergic reactions. We have previously demonstrated that human airway smooth muscle (ASM) cells express the tetrameric (αβγ2) FcεRI, and its activation leads to marked transient increases in intracellular Ca²⁺ concentration, release of Th-2 cytokines and eotaxin-1/CCL11. Therefore, it was of utmost importance to delineate the factors regulating the expression of FcεRI in human (ASM) cells.

Methodology/Principal Findings

Incubation of human bronchial and tracheal smooth muscle (B/TSM) cells with TNF-α, IL-1β or IL-4 resulted in a significant increase in FcεRI-α chain mRNA expression (p<0.05); and TNF-α, IL-4 enhanced the FcεRI-α protein expression compared to the unstimulated control at 24, 72 hrs after stimulation. Interestingly, among all other cytokines, only TNF-α upregulated the FcεRI-γ mRNA expression. FcεRI-γ protein expression remained unchanged despite the nature of stimulation. Of note, as a functional consequence of FcεRI upregulation, TNF-α pre-sensitization of B/TSM potentially augmented the CC (eotaxin-1/CCL11 and RANTES/CCL5, but not TARC/CCL17) and CXC (IL-8/CXCL8, IP-10/CXCL10) chemokines release following IgE stimulation (p<0.05, n = 3). Furthermore, IgE sensitization of B/TSM cells significantly enhanced the transcription of selective CC and CXC chemokines at promoter level compared to control, which was abolished by Lentivirus-mediated silencing of Syk expression.

Conclusions/Significance

Our data depict a critical role of B/TSM in allergic airway inflammation via potentially novel mechanisms involving proinflammatory, Th2 cytokines and IgE/FcεRI complex.

Respiratory defenses in health and disease

Every breath holds the potential to introduce infectious organisms and irritating particulates into the respiratory tract. Despite this continuous exposure, the lungs usually remain sterile. Further, potential pathogens are distinguished from innocuous particulates, thus sparing the respiratory tract from damaging inflammation. The article reviews the complex defenses used to protect the respiratory tract and also discusses the implications of failed defense systems.

Difficult to control asthma in children

PURPOSE OF REVIEW

The management of children with difficult asthma requires a systematic approach. These children are prescribed high doses of inhaled or oral corticosteroids and a balance must be struck between therapeutic efficacy and side effects. It is important to ensure the diagnosis is correct and that the reasons for poor control in a given child are characterized so that treatment can be targeted for maximal effect.

RECENT FINDINGS

Recent data have demonstrated the correlation between invasive and noninvasive measurement of airway eosinophils. Noninvasive markers of inflammation can be used to determine phenotype and there is increasing evidence on the utility of repeated measures to monitor control and treatment effects. Side effects of high-dose corticosteroids remain a concern. The emergence of new therapies may be of benefit. These are often expensive, however, and have the potential for major side effects. Adherence remains a significant obstacle to the effective management of difficult asthma.

SUMMARY

Children with difficult asthma are a heterogeneous group. Characterization and monitoring of these children can be enhanced by measurements of noninvasive markers of inflammation. Further evaluation of new and phenotype-specific treatments for children with difficult asthma need to be evaluated in prospective randomized controlled trials.