shRNA targeting β1-integrin suppressed proliferative aspects and migratory properties of airway smooth muscle cells

The Regulatory Role of miR-107-Cdk6-Rb Pathway in Airway Smooth Muscle Cells in Asthma

Purpose

Airway remodeling is a significant pathological change of asthma. This study aimed to detect differentially expressed microRNAs in the serum of asthma patients and airway smooth muscle cells (ASMCs) of asthmatic mice, exploring their role in the airway remodeling of asthma.

Methods

The differentially expressed microRNAs in the serum of mild and moderate-severe asthma patients compared to healthy subjects were revealed using the "limma" package. Gene Ontology (GO) analysis was used to annotate the functions of microRNA target genes. The relative expressions of miR-107 (miR-107-3p in mice sharing the same sequence) in the primary airway smooth muscle cells (ASMCs) of the asthma mice model were tested by RT-qPCR. Cyclin-dependent kinases 6 (Cdk6), a target gene of miR-107, was predicted by algorithms and validated by dual-luciferase reporter assay and Western blot. The roles of miR-107, Cdk6, and protein Retinoblastoma (Rb) in ASMCs were examined by transwell assay and EDU KIT in vitro.

Results

The expression of miR-107 was down-regulated in both mild and moderate-severe asthma patients. Intriguingly, the level of miR-107 was also decreased in ASMCs of the asthma mice model. Up-regulating miR-107 suppressed ASMCs' proliferation by targeting Cdk6 and the phosphorylation level of Rb. Increasing the expression of Cdk6 or suppressing Rb activity abrogated the proliferation inhibition effect of ASMCs induced by miR-107. In addition, miR-107 also inhibits ASMC migration by targeting Cdk6.

Conclusion

The expression of miR-107 is down-regulated in serums of asthma patients and ASMCs of asthmatic mice. It plays a critical role in regulating the proliferation and migration of ASMCs via targeting Cdk6.

SET knockdown attenuated phenotype modulation and calcium channel associated markers of airway smooth muscle cells in asthmatic mice

Background

Dysfunctional phenotype modulation and calcium channels in airway smooth muscle cells (ASMCs) are important characteristics of airway remodeling in chronic asthma. However, the mechanisms underlying these pathological processes remain unclear. SET (I2PP2A, inhibitor-2 of protein phosphatase 2A) has many significant functions and is involved in various physiological and pathological processes. This study aimed to determine the function of SET in chronic asthma.

Methods

BALB/c mice were sensitized by ovalbumin injection and repeated inhalation of ovalbumin. The Penh value was measured using the Buxco whole body plethysmography system. A short hairpin RNA of the SET gene was designed and transfected into ASMCs derived from asthmatic mice. Flow cytometry of Annexin-V/propidium iodide staining was used for evaluating cell apoptosis. Western blot was adopted to measure the expression levels of ASMCs phenotype modulation markers and calcium channel-associated proteins.

Results

The results showed that shRNA targeting SET significantly decreased the expression of SET, and enhanced the apoptosis of ASMCs. SET knockdown promoted the expression of contractile phenotype markers such as α-SMA (alpha smooth muscle Actin), SM-MHC (smooth muscle Myosin heavy chain), and calponin, and inhibited the expression of synthetic phenotype markers including vimentin and CD44. The expression of the calcium channel-related proteins STIM1 (Stromal interaction molecule 1) and Orai1 were also inhibited after SET knockdown.

Conclusions

These data demonstrated that SET participated in the development of airway dysfunction in asthma, suggesting that the silencing of SET may be a new therapeutic target for the treatment of asthma patients.

The Role of TNF Family Molecules Light in Cellular Interaction Between Airway Smooth Muscle Cells and T Cells During Chronic Allergic Inflammation

Interaction between T cells and airway smooth muscle (ASM) cells has been identified as an important factor in the development of asthma. LIGHT (known as TNFSF14) -mediated signaling likely contributes to various inflammatory disorders and airway remodeling. The objective of this study was to investigate the roles of LIGHT-mediated pathways in the interaction between ASM cells and T cells during chronic allergic inflammation. Mice were sensitized and challenged by ovalbumin (OVA) to induce chronic airway allergic inflammation. The control group received PBS only. The histological features and LIGHT expressions in lungs were assessed in vivo. Furthermore, T cells and ASM cells derived from the model mice were co-cultured both in the presence and absence of anti-LIGHT Ab for 72 h. The effects of LIGHT blockade on expressions of downstream signaling molecules, proliferation, and apoptosis of ASM cells, differentiation of T cells, and inflammatory cytokines release were evaluated. We demonstrated that LIGHT blockade strikingly inhibited the mRNA and protein expressions of HVEM, c-JUN, and NFκB. Additionally, LIGHT blockade resulted in decreased proliferation and increased apoptosis of ASM cells. Moreover, depletion of LIGHT dramatically reduced the differentiation of CD4⁺ T cells into Th1, Th2, and Th17 cells, as well as inhibited inflammatory cytokines release including IL-13, TGF-β, and IFN-γ, which are associated with CD4⁺ T cell differentiation and ASM cell proliferation. LIGHT plays an important role in the interaction between T cells and ASM cells in chronic allergic asthma. Blockade of LIGHT markedly suppressed ASM hyperplasia and inflammatory responses, which might be modulated through HVEM-NFκB or c-JUN pathways. Therefore, targeting LIGHT is a promising therapeutic strategy for airway inflammation and remodeling in chronic allergic asthma.

Fibulin-5 promotes airway smooth muscle cell proliferation and migration via modulating Hippo-YAP/TAZ pathway

Asthma is a common chronic disease mainly occurs from childhood. Increased airway smooth muscle mass is involved in the pathogenesis of asthma. Fibulin-5 was upregulated in the lung tissues of patients with COPD and idiopathic pulmonary fibrosis. This study aimed to investigate Fibulin-5 expression in asthmatic patients and the effect and mechanism of Fibulin-5 on the proliferation and migration of airway smooth muscle cells (ASMCs). The expression of Fibulin-5, YAP, and TAZ in the induced sputum of 38 asthmatic children (19 mild and 19 moderate asthmatics) and 19 healthy controls was determined. The effects and mechanisms of Fibulin-5 on the proliferation and migration of ASMCs were analyzed through upregulating Fibulin-5. We found compared with healthy controls, the expression of Fibulin-5, YAP, and TAZ was increased in the induced sputum of asthmatic children and much higher in moderate asthmatics. Fibulin-5 overexpression promoted the proliferation and migration of ASMCs, upregulated the expression of YAP and TAZ, and reduced the levels of p-YAP and p-TAZ. YAP inhibitor (Peptide 17) abrogated the proliferation and migration of ASMCs induced by Fibulin-5 overexpression in a dose-dependent manner. Additionally, Fibulin-5 overexpression enhanced its binding capacity of β1 integrin, and β1 integrin blocking antibody partly reversed the effect of Fibulin-5 overexpression on the levels of YAP and TAZ. In conclusion, Fibulin-5 expression is correlated with the pathogenesis of childhood asthma. It may function at least partly through binding to β1 integrin and modulating Hippo-YAP/TAZ pathway to promote the proliferation and migration of ASMCs.

Silencing of β1 integrin regulates airway remodeling by regulating the transcription of SOCE‑associated genes in asthmatic mice

The incidence of asthma is increasing globally; however, current treatments are only able to cure a certain proportion of patients. There is an urgent need to develop novel therapies. β1 integrin serves a role in the pathophysiology of asthma through the development of airway remodeling. The aim of the present study was to investigate silencing of the β1 integrin gene in pre-clinical models of allergic asthma. BALB/c mice were sensitized with ovalbumin through intraperitoneal injection and repeated aerosolized ovalbumin. A short hairpin RNA of the β1 integrin gene was designed and transfected into mouse models of asthma in vivo, in order to evaluate whether silencing of the β1 integrin gene affects airway smooth muscle cell proliferation and inflammation by regulating the mRNA expression of store-operated Ca²⁺ entry (SOCE)-associated genes. Silencing the β1 integrin gene may downregulate β1 integrin mRNA while not statistically decreasing α-smooth muscle actin gene expression and airway smooth muscle thickness. β1 integrin silencing was able to downregulate the transcription of SOCE-associated genes to normal levels, including calcium release-activated calcium modulator 1 and short transient receptor potential channel member 1, but not stromal interaction molecule 1, in asthma. Silencing of the β1 integrin gene additionally maintained nuclear factor of activated T-cells cytoplasmic 1 gene expression, and inflammatory cytokines interleukin-4 and interferon-γ at normal levels. The results of the present study provide evidence to suggest that silencing of the β1 integrin gene may be of therapeutic benefit for patients with asthma.

Genetic variation of ITGB3 is associated with asthma in Chinese Han children

Previous studies have demonstrated that integrins are involved in the aetiology of asthma. Several single-nucleotide polymorphisms (SNPs) in the integrin β3 (ITGB3) gene are significantly associated with asthma in Western populations. Given the important roles of environmental exposures in the development of asthma, we evaluated the associations between six SNPs in ITGB3 and asthma in Chinese Han children. A total of 321 unrelated Chinese children with asthma and 315 healthy children were recruited for the study. SNP genotyping was performed by high-resolution melting analysis (HRM). The selected SNPs were well genotyped by HRM, and SNP rs3809865 in the 3′ untranslated region (3′UTR) of ITGB3 was found to be strongly associated with asthma (adjusted p = 0.004). The minor allele of rs3809865 showed a protective effect against asthma (OR: 0.59; 95% CI: 0.43–0.8). The seed regions of two miRNAs (hsa-mir-124 and hsa-mir-506) were predicted to bind to the sequence containing rs3809865 by TargetScan and PITA. Luciferase reporter assays demonstrated that the T allele of rs3809865 was more efficiently targeted by hsa-mir-124 than was the A allele, which suggested that rs3809865 could affect the binding of hsa-mir-124 to ITGB3. Furthermore, the transfection of A549 cells with hsa-mir-124 resulted in the downregulation of ITGB3 expression. Our results revealed that rs3809865 was significantly associated with asthma due to its effect on the binding of hsa-mir-124 to ITGB3.

Smooth muscle in tissue remodeling and hyper-reactivity: airways and arteries

Smooth muscle comprises a key functional component of both the airways and their supporting vasculature. Dysfunction of smooth muscle contributes to and exacerbates a host of breathing-associated pathologies such as asthma, chronic obstructive pulmonary disease and pulmonary hypertension. These diseases may be marked by airway and/or vascular smooth muscle hypertrophy, proliferation and hyper-reactivity, and related conditions such as fibrosis and extracellular matrix remodeling. This review will focus on the contribution of airway or vascular smooth dysfunction to common airway diseases.