Prospects for new and emerging therapeutics in severe asthma: the role of biologics

Human bone marrow-mesenchymal stem cell-derived exosomal microRNA-188 reduces bronchial smooth muscle cell proliferation in asthma through suppressing the JARID2/Wnt/β-catenin axis

The functions of exosomes in allergic diseases including asthma have aroused increasing concerns. This paper focuses on the effects of exosomes derived from human bone marrow-mesenchymal stem cells (hBM-MSCs) on the proliferation of bronchial smooth muscle cells in asthma and the mechanism involved. Exosomes were extracted from hBM-MSCs and identified. Human BSMCs were induced with transforming growth factor (TGF)-β1 to mimic an asthma-like condition in vitro and then treated with exosomes. A mouse model with asthma was induced by ovalbumin (OVA) and treated with exosomes for in vivo study. The hBM-MSC-derived exosomes significantly reduced the abnormal proliferation and migration of TGF-β1-treated BSMCs. microRNA (miR)-188 was the most enriched miRNA in exosomes according the microarray analysis, and JARID2 was identified as a mRNA target of miR-188. Either downregulation of miR-188 or upregulation of JARID2 blocked the protective effects of exosomes on BSMCs. JARID2 activated the Wnt/β-catenin signaling pathway. In the asthmatic mice, hBM-MSC-derived exosomes reduced inflammatory cell infiltration, mucus production, and collagen deposition in mouse lung tissues. In conclusion, this study suggestes that hBM-MSC-derived exosomes suppress proliferation of BSMCs and lung injury in asthmatic mice through the miR-188/JARID2/Wnt/β-catenin axis. This study may provide novel insights into asthma management.

Glucocorticoid induced transcript 1 represses airway remodeling of asthmatic mouse via inhibiting IL-13/periostin/TGF-β1 signaling

Asthma is characterized by airway remodeling. Glucocorticoid induced transcript 1 (GLCCI1) was reported to be associated with the development of asthma, while its exact mechanism is still not clear. In our study, ovalbumin (OVA) combined with aluminum hydroxide were used to establish asthmatic mouse model. ELISA assay was fulfilled to ensure the concentration of inflammatory factors in both bronchoalveolar lavage fluid and serum. The pathological changes and collagen deposition in lung tissues were analyzed using H&E staining and Masson staining, respectively. The expression of proteins was measured using western blot, and the expression of GLCCI1 mRNA was ensured by qRT-PCR. Here, we demonstrated that OVA-induced inflammation, lung structural remodeling and collagen deposition in asthmatic mice was notably improved by hydroprednisone treatment or GLCCI1 overexpressing. The expression of GLCCI1 was decreased, while IL-13, periostin and TGF-β1 were increased in the lung tissue of asthmatic mice. Importantly, upregulation of GLCCI1 suppressed the expression of IL-13, periostin and TGF-β1, phosphorylation of Smad2 and Smad3, and extracellular matrix (ECM) deposition-related proteins expression. IL-13-induced upregulation of periostin and TGF-β1 expression, phosphorylation of Smad2 and Smad3, and ECM deposition in airway epithelial cells (AECs) was repressed by GLCCI1 increasing. Furthermore, our results showed that overexpression of GLCCI1 repressed the effect of IL-13 on AECs via inhibiting periostin expression. Overall, our data revealed that GLCCI1 limited the airway remodeling in mice with asthma through inhibiting IL-13/periostin/TGF-β1 signaling pathway. Our data provided a novel target for asthma treatment.

miR-135a inhibits airway inflammatory response in asthmatic mice via regulating JAK/STAT signaling pathway

The objective of this study was to investigate the inhibitory effect of miR-135a in regulating JAK/STAT signaling pathway on airway inflammation in asthmatic mice. An asthma model was established by sensitization and stimulation with ovalbumin (OVA), and the corresponding drug intervention was given from the day of stimulation by means of nasal drops. Airway hyperresponsiveness was tested. The content of miR-135a in the lung tissue of mice was detected by RT-PCR. The pathological changes of lung tissue were evaluated by HE staining. Tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-5, and eotaxin in bronchoalveolar lavage fluid (BALF) and lung tissue were detected by ELISA and immunohistochemistry, respectively. The expression of JAK/STAT signaling pathway-related protein in lung tissue was detected by western blot. To further validate the effect of miR-135a overexpression on the JAK/STAT signaling pathway, pathway activators and inhibitors were added. Compared with the OVA group, the airway hyperresponsiveness of the mice was significantly decreased after treatment with the miR-135a agonist. The expression of miR-135a was significantly increased in the lung tissue and the pathological changes of the lung tissue were alleviated. The contents of TNF-α, IL-6, IL-5, and eotaxin in BALF and lung tissues were decreased. The expression of JAK/STAT signaling pathway-related proteins p-JAK3/JAK3, p-STAT1/STAT1, and p-STAT3/STAT3 were significantly reduced in lung tissue (P<0.05). Addition of JAK inhibitor AG490 reduced airway inflammation in asthmatic mice. miR-135a agonists inhibit airway inflammation in asthmatic mice by regulating the JAK/STAT signaling pathway.

A narrative review of research advances in mesenchymal stem cell therapy for asthma

Asthma is a chronic inflammatory disease of the airways that involves multiple cells, including inflammatory cells, structural cells, and cellular components. Glucocorticoids and beta-receptor agonists are still the first choices for asthma treatment. However, the asthma symptoms may still be poorly controlled in some patients after an optimal treatment. Mesenchymal stem cells (MSCs) are characterized by the potential for multi-directional differentiation and can exert immunomodulatory and anti-inflammatory effects. Its role in treating asthma has increasingly been recognized in recent years. In this review article, we sought to summarize the recent advances in the therapeutic effects of MSCs on several types of asthma and explain the relevant mechanisms. Articles on asthma treatment with MSCs as of January 2020 were searched in PubMed, Google Scholar, and Web of Science databases. It was found that MSCs have therapeutic effects on allergic asthma, non-allergic asthma and occupational asthma; gene-modified or pretreated MSCs improves the therapeutic effects of MSCs in asthma; MSC-derived conditioned medium or extracellular vesicles possess the considerable curative effect as MSC on asthma; and MSCs exert their therapeutic effects on asthma by restoring Th1/Th2 balance, reversing Th17/Tregs imbalance, inhibiting DC maturation, and promoting the switch of M1 to M2 and repairing epithelial injury. Thus, MSCs may be a promising treatment for asthma.

Semaphorin 4A Stabilizes Human Regulatory T Cell Phenotype via Plexin B1

We previously reported that neuroimmune semaphorin (Sema) 4A regulates the severity of experimental allergic asthma and increases regulatory T (Treg) cell numbers in vivo; however, the mechanisms of Sema4A action remain unknown. It was also reported that Sema4A controls murine Treg cell function and survival acting through neuropilin 1 (NRP-1) receptor. To clarify Sema4A action on human T cells, we employed T cell lines (HuT78 and HuT102), human PBMCs, and CD4+ T cells in phenotypic and functional assays. We found that HuT78 demonstrated a T effector-like phenotype (CD4+CD25lowFoxp3-), whereas HuT102 expressed a Treg-like phenotype (CD4+CD25hi Foxp3+). Neither cell line expressed NRP-1. HuT102 cells expressed Sema4A counter receptor Plexin B1, whereas HuT78 cells were Sema4A+. All human peripheral blood CD4+ T cells, including Treg cells, expressed PlexinB1 and lacked both NRP-1 and -2. However, NRP-1 and Sema4A were detected on CD3negativeCD4intermediate human monocytes. Culture of HuT cells with soluble Sema4A led to an upregulation of CD25 and Foxp3 markers on HuT102 cells. Addition of Sema4A increased the relative numbers of CD4+CD25+Foxp3+ cells in PBMCs and CD4+ T cells, which were NRP-1negative but PlexinB1+, suggesting the role of this receptor in Treg cell stability. The inclusion of anti-PlexinB1 blocking Ab in cultures before recombinant Sema4A addition significantly decreased Treg cell numbers as compared with cultures with recombinant Sema4A alone. Sema4A was as effective as TGF-β in inducible Treg cell induction from CD4+CD25depleted cells but did not enhance Treg cell suppressive activity in vitro. These results suggest strategies for the development of new Sema4A-based therapeutic measures to combat allergic inflammatory diseases. ImmunoHorizons, 2019, 3: 71-87.

Controversies and opportunities in severe asthma

PURPOSE OF REVIEW

Despite currently available treatments, many asthma patients remain inadequately controlled, but identifying distinct patient populations (phenotypes/endotypes) may optimize their management. This review discusses some of the controversies and opportunities for improved disease control in severe asthma.

RECENT FINDINGS

Currently approved anti-immunoglobulin E and anti-interleukin 5 biologics, which target specific pathways instead of using a 'one size fits all' strategy, are efficacious and well tolerated therapies for severe asthma. The appropriate use of these biologics, and of those in development (e.g., benralizumab and dupilumab), should be aided by further understanding of asthma phenotypes and endotypes, utilizing appropriate biomarkers.Oral corticosteroids are often added as maintenance therapy for patients with severe uncontrolled asthma, but their use is associated with significant adverse effects and should be considered a last option. The true cost of this therapy, including the cost of morbidities associated with its use, remains to be determined.Severe asthma in pediatrics poses a unique opportunity for possible prevention strategies and the potential for primary prevention. Although several avenues for primary prevention are being explored and are out of the scope of this review, we focus our discussion on the use of omalizumab, which has been recently explored in clinical trials.

SUMMARY

Appropriate use of biologics in severe asthma should be supported by further understanding of biomarkers predicting response to targeted therapy. Because of their association with significant adverse effects, add-on oral corticosteroids should be considered a last treatment option for patients with uncontrolled severe asthma. Finally, severe asthma in pediatrics poses a unique opportunity for potential prevention strategies.

Toward Better Management for Asthma: From Smart Inhalers to Injections to Wearables, Researchers Are Finding New Ways to Improve Asthma Treatment

Although asthma has been around since Hippocrates' time, more people are being diagnosed with the disease than ever before. Over the last 20 years, the global burden of asthma has increased by almost 30%, as more than 235 million people-most of them children-cope with the breathlessness and wheezing characteristic of the disease. In particular, cases have spiked in China and India, where pollution is reported to sometimes be deadly. Researchers with the Health Effects Institute, a Boston-based nonprofit that studies the health effects of pollution, recently reported that air pollution in India and China alone contributed to more than half of the four million deaths worldwide due to air pollution in 2015.