Chronic asthma and Mesenchymal stem cells: Hyaluronan and airway remodeling

Mesenchymal Stem/Stromal Cells in Asthma Therapy: Mechanisms and Strategies for Enhancement

Asthma is a complex and heterogeneous disease characterized by chronic airway inflammation, airway hyperresponsiveness, and airway remodeling. Most asthmatic patients are well-established using standard treatment strategies and advanced biologicals. However, a small group of patients who do not respond to biological treatments or are not effectively controlled by available treatment strategies remain a clinical challenge. Therefore, new therapies are urgently needed for poorly controlled asthma. Mesenchymal stem/stromal cells (MSCs) have shown therapeutic potential in relieving airway inflammation and repairing impaired immune balance in preclinical trials owing to their immunomodulatory abilities. Noteworthy, MSCs exerted a therapeutic effect on steroid-resistant asthma with rare side effects in asthmatic models. Nevertheless, adverse factors such as limited obtained number, nutrient and oxygen deprivation in vitro, and cell senescence or apoptosis affected the survival rate and homing efficiency of MSCs, thus limiting the efficacy of MSCs in asthma. In this review, we elaborate on the roles and underlying mechanisms of MSCs in the treatment of asthma from the perspective of their source, immunogenicity, homing, differentiation, and immunomodulatory capacity and summarize strategies to improve their therapeutic effect.

Human bone marrow-derived mesenchymal stem cells rescue neonatal CPAP-induced airway hyperreactivity

Continuous positive airway pressure (CPAP) is a primary non-invasive mode of respiratory support for preterm infants. However, emerging evidence suggests CPAP could be an underlying contributor to the unintended pathophysiology of wheezing and associated airway hyperreactivity (AHR) in former preterm infants. The therapeutic benefits of mesenchymal stem cells (MSCs) have been demonstrated in a variety of animal models and several clinical trials are currently underway to assess their safety profiles in the setting of prematurity and bronchopulmonary dysplasia (BPD). In the present study, using a mouse model of neonatal CPAP, we investigated whether conditioned medium harvested from cultures of human bone-marrow derived mesenchymal stem cells (hMSC) could rescue the CPAP-induced AHR, based upon previous observations of their anti-AHR properties. Newborn mice (male and female) were fitted with a custom-made mask for delivery of daily CPAP 3 h/day for the first 7 postnatal days. At postnatal day 21 (two weeks after CPAP ended), lungs were removed, precision-cut lung slices were sectioned and incubated for 48 h in vitro in conditioned medium collected from cultures of three different hMSC donors. As expected, CPAP resulted in AHR to methacholine compared to untreated control mice. hMSC conditioned medium from the cultures of all three donors completely reversed AHR. These data reveal potential therapeutic benefits of hMSC therapy, which may be capable of rescuing the long-term adverse effects of neonatal CPAP on human airway function.

Chronic obstructive pulmonary disease and asthma: mesenchymal stem cells and their extracellular vesicles as potential therapeutic tools

Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, are one of the most frequent causes of morbidity and mortality in the global. COPD is characterized by progressive loss of lung function through inflammation, apoptosis, and oxidative stress caused by chronic exposure to harmful environmental pollutants. Airway inflammation and epithelial remodeling are also two main characteristics of asthma. In spite of extensive efforts from researchers, there is still a great need for novel therapeutic approaches for treatment of these conditions. Accumulating evidence suggests the potential role of mesenchymal stem cells (MSCs) in treatment of many lung injuries due to their beneficial features including immunomodulation and tissue regeneration. Besides, the therapeutic advantages of MSCs are chiefly related to their paracrine functions such as releasing extracellular vesicles (EVs). EVs comprising exosomes and microvesicles are heterogeneous bilayer membrane structures loaded with various lipids, nucleic acids and proteins. Due to their lower immunogenicity, tumorigenicity, and easier management, EVs have appeared as favorable alternatives to stem cell therapies. Therefore, in this review, we provided an overview on the current understanding of the importance of MSCs and MSC-derived EVs from different sources reported in preclinical and clinical COPD and asthmatic models.

Intra-tracheal delivery of mesenchymal stem cell-conditioned medium ameliorates pathological changes by inhibiting apoptosis in asthmatic rats

BACKGROUND

Asthma, an inflammatory illness of the lungs, remains the most common long-term disease amongst children. This study tried to elaborate the status of apoptosis in asthmatic pulmonary niche after the application of rat mesenchymal stem cells (MSC-CM)-derived secretome.

METHODS AND RESULTS

Here, we randomly allocated male Wistar rats into three groups (n = 8); Control animals were intratracheally given 50 μl vehicle. In control-matched sensitized rats, 50 μl normal saline was used. In the last group, 50 μl MSC-CM was applied. Two-week post-administration, transcription of T-bet, GATA-3, Bax, Bcl-2 and Caspase-3 was measured by gene expression analysis. Pathological injuries were monitored using H&E staining. The BALF level of TNF-α was measured using ELISA assay. In asthmatic rats received MSC-CM, the expression of T-bet was increased while the level of GATA-3 decreased compared to the S group (p < 0.05). Levels of BALF TNF-α were suppressed in asthmatic niche after MSC-CM administration (p < 0.05). Compared to the asthmatic group, MSC-CM had potential to alter the expression of apoptosis-related genes in which the expression of Bax and Caspase 3 was decreased and the expression of pro-survival factor, Bcl-2 increased (p < 0.05).

CONCLUSION

Our data notified the potency of direct administration of MSC-CM in the alleviation of airway inflammation, presumably by down regulating apoptotic death in pulmonary niche.

Atractylodin attenuates the expression of MUC5AC and extracellular matrix in lipopolysaccharide-induced airway inflammation by inhibiting the NF-κB pathway

This study aimed to explore the effects of atractylodin (ATR) on lipopolysaccharide (LPS)-induced inflammatory response in human airway epithelial cells. The cytotoxicity was assessed by CCK-8 assay. The mRNA expression and concentration of interleukin (IL)-6, IL-8, and mucin 5AC (MUC5AC) were measured by qRT-PCR and ELISA, respectively. Western blotting was performed to determine protein expression. We found that LPS stimulation increased the mRNA expression and concentrations of IL-6, IL-8, and MUC5AC, as well as the expression of Col-I and FN in 16HBE cells, but this effect of LPS was attenuated by ATR treatment. Mechanistically, ATR suppressed LPS-induced activation of the NF-κB pathway in 16HBE cells. Moreover, ATR repressed ovalbumin-induced airway inflammation and NF-kB pathway in mice. In conclusion, ATR attenuated the expression of MUC5AC and ECM in LPS-induced airway inflammation by inhibiting the NF-κB pathway.

Donor-defined mesenchymal stem cell antimicrobial potency against nontuberculous mycobacterium

Chronic nontuberculous mycobacterial infections with Mycobacterium avium and Mycobacterium intracellulare complicate bronchiectasis, chronic obstructive airway disease, and the health of aging individuals. These insidious intracellular pathogens cause considerable morbidity and eventual mortality in individuals colonized with these bacteria. Current treatment regimens with antibiotic macrolides are both toxic and often inefficient at providing infection resolution. In this article, we demonstrate that human marrow‐derived mesenchymal stem cells are antimicrobial and anti‐inflammatory in vitro and in the context of an in vivo sustained infection of either M. avium and/or M. intracellulare.

Unraveling the therapeutic effects of mesenchymal stem cells in asthma

Asthma is a chronic inflammatory disease associated with airway hyper-responsiveness, chronic inflammatory response, and excessive structural remodeling. The current therapeutic strategies in asthmatic patients are based on controlling the activity of type 2 T helper lymphocytes in the pulmonary tissue. However, most of the available therapies are symptomatic and expensive and with diverse side outcomes in which the interruption of these modalities contributes to the relapse of asthmatic symptoms. Up to date, different reports highlighted the advantages and beneficial outcomes regarding the transplantation of different stem cell sources, and relevant products from for the diseases' alleviation and restoration of injured sites. However, efforts to better understand by which these cells elicit therapeutic effects are already underway. The precise understanding of these mechanisms will help us to translate stem cells into the clinical setting. In this review article, we described current knowledge and future perspectives related to the therapeutic application of stem cell-based therapy in animal models of asthma, with emphasis on the underlying therapeutic mechanisms.

Mesenchymal stem cells in allergic diseases: Current status

Allergic diseases, which include asthma, allergic skin diseases, allergic rhinitis and allergic conjunctivitis, have already garnered worldwide public health attention over recent decades. Mesenchymal stem cells (MSCs) have gradually emerged as a potential method for treating allergic diseases due to their immunosuppressive characteristics, tissue repair ability and secretion of various biological factors. This potential of MSC-based therapy has been confirmed in clinical and preclinical studies, which report the therapeutic benefits of MSCs for various allergic diseases and explore the antiallergic mechanisms. In this review, we focus on the discoveries and biological mechanisms of MSCs as a therapeutic tool in allergic diseases. We discuss the challenges of conducting MSC studies as well as future directions.

Insights into animal models for cell-based therapies in translational studies of lung diseases: Is the horse with naturally occurring asthma the right choice?

Human asthma is a widespread disease associated with chronic inflammation of the airways, leading to loss of quality of life, disability and death. Corticosteroid administration is the mainstream treatment for asthmatic patients. Corticosteroids reduce airway obstruction and improve quality of life, although symptoms persist despite treatment in many patients. Moreover, available therapies failed to reverse the lung pathology present in asthma. Animal models, mostly rats and mice, in which the disease is experimentally induced, have been studied to identify new therapeutic targets for human asthma. Alternative animal models could include horses in which naturally occurring asthma could represent an important step to test therapies, potentially designed around mouse studies, before being translated to human testing. Horses naturally suffer from asthma, which has striking parallels with human asthma. Severe equine asthma (SEA) is characterized by reversible bronchospasms and neutrophil accumulation in the lungs immunologically mediated mainly by Th2. Moreover, the pulmonary remodelling that occurs in SEA closely resembles that of human asthma, making the equine model unique for investigation of tissue repair and new therapies. Cell therapy, consisting on mesenchymal stromal cells (MSCs) and derivatives (conditioned medium and extracellular vesicles), could represent a novel therapeutic contribution for tissue regeneration. Cell therapy may prove advantageous over conventional therapy in that it may repair or regenerate the site of injury and reduce the reaction to allergens, rather than simply modulating the inflammatory process.

Mesenchymal stem cells for inflammatory airway disorders: promises and challenges

The regenerative and immunomodulatory characteristics of mesenchymal stem cells (MSCs) make them attractive in the treatment of many diseases. Although they have shown promising preclinical studies of immunomodulation and paracrine effects in inflammatory airway disorders and other lung diseases, there are still challenges that have to be overcome before MSCs can be safely, effectively, and routinely applied in the clinical setting. A good understanding of the roles and mechanisms of the MSC immunomodulatory effects will benefit the application of MSC-based clinical therapy. In this review, we summarize the promises and challenges of the preclinical and clinical trials of MSC therapies, aiming to better understand the role that MSCs play in attempt to treat inflammatory airway disorders.

Casticin alleviates lipopolysaccharide-induced inflammatory responses and expression of mucus and extracellular matrix in human airway epithelial cells through Nrf2/Keap1 and NF-κB pathways

Asthma is one of the most common chronic inflammatory diseases of childhood, characterized by airway inflammation, mucus hypersecretion, and accumulation of extracellular matrix proteins. Casticin is an active compound that possesses broad biological activities including anti-inflammatory effect. However, the effect of casticin on asthma remains unknown. The aim of the present study was to evaluate the effect and mechanism of casticin on inflammatory responses and expression of mucus and extracellular matrix in human airway epithelial cells. The results showed that lipopolysaccharide induced the mRNA and protein levels of IL-6, IL-8, MUC5AC, collagen type I, and fibronectin in 16-HBE cells, whereas casticin treatment significantly inhibited the induction of lipopolysaccharide. Casticin induced Nrf2/Keap1 and inhibited nuclear factor κB pathways in 16-HBE cells. Knockdown of Nrf2 attenuated the effect of casticin on production of IL-6 and IL-8, expression of MUC5AC, collagen type I, and fibronectin in 16-HBE cells. In conclusion, the results indicated that casticin might be a novel therapeutic strategy for the treatment of asthma.