MicroRNA-200a Affects the Proliferation of Airway Smooth Muscle Cells and Airway Remodeling by Targeting FOXC1 via the PI3K/AKT Signaling Pathway in Ovalbumin-Induced Asthmatic Mice.

The etiology of asthma, which is a complicated disorder with various symptoms, including wheezing, coughing, and airflow obstruction, remains poorly understood. In addition, the effects of microRNAs (miRs) have not been explored. This study explored the effect of microRNA-200a (miR-200a) on airway smooth muscle cells (ASMCs) and airway remodeling in asthmatic mice. Furthermore, we speculated that miR-200a achieves its effect by targeting FOXC1 via the PI3K/AKT signaling pathway based on differentially expressed gene screening, target miR predictions and a bioinformatics analysis. Eighty mice were assigned to a saline group or an ovalbumin (OVA) group, and the OVA group was transfected with a series of inhibitors, activators, and siRNAs to test the established mouse model. Airway reactivity and the ratio of eosinophils (EOSs) to leukocytes were detected. An ELISA was adopted to measure the levels of interleukin (IL)-4, IL-6, IL-8, tumor necrosis factor (TNF)-α, and immunoglobulin E (IgE). Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to determine the expression of FOXC1, PI3K, AKT, NF-κB, cyclin D1, TGF-β1 and p-AKT in ASMCs. Finally, CCK-8 assays were performed to detect cell proliferation and flow cytometry to detect apoptosis and cell cycle entry. The bioinformatics analysis indicated that miR-200a mediated the PI3K/AKT signaling pathway by targeting FOXC1. In addition, mouse models of asthma were established. An elevated expression of miR-200a, a decreased mRNA and protein expression of FOXC1, PI3K, AKT, NF-κB, cyclin D1 and TGF-β1, a decreased expression of p-AKT, suppressed cell proliferation, accelerated apoptosis, and an increased number of cells at the G0/G1 phase were observed following the upregulation of miR-200a and downregulation of FOXC1. The overexpression of miR-200a may downregulate FOXC1, thereby inhibiting the activation of the PI3K/AKT signaling pathway and ultimately suppressing ASMC proliferation and airway remodeling in asthmatic mice. This evidence supports the potential that miR-200a represents a new approach to treating asthma.

Liu Y ，Miao Y ，Gao X ，Wang YY ，Wang H ，Zheng YW ，Zhao ZY ... -  《-》

Isorhynchophylline exerts anti-asthma effects in mice by inhibiting the proliferation of airway smooth muscle cells: The involvement of miR-200a-mediated FOXC1/NF-κB pathway.

Hyperplasia of airway smooth muscle cells (ASMCs) is key to the progression of asthma. Isorhynchophylline (IRN) derived from Uncaria rhynchophylla can inhibit the proliferation of AMSCs. The major purpose of the current study was to assess the effect of IRN on the asthma symptoms was assessed both in vitro and in vivo, and the associated mechanism of the effect was also explored by focusing on the function of miR-200a. Asthma model was induced using ovalbumin (OVA) method and AMSC hyperplasia model was induced using TGF-β1. The effect of IRN on allergic asthma mice and the effect of IRN on the proliferation of ASMCs were investigated as well, and the changes in miR-200a level and FOXC1/NF-κB pathway were detected. The administration of IRN attenuated the eosinophils recruitment in BALF, reduced collagen deposition in lung tissues, and suppressed production of IgE and pro-inflammation cytokines. IRN also inhibited the proliferation and induced the apoptosis of ASMCs. Moreover, the administration of IRN increased the level of miR-200a while inhibited the activation of FOXC1/NF-κB pathway. However, after the inhibition of miR-200a level, the function of IRN on ASMCs was impaired. Collectively, it was demonstrated that the effect of IRN on asthma relied on the up-regulation of miR-200a, which then deactivated FOXC1/NF-κB pathway.

Zhu J ，Wang W ，Wu X 《-》

MicroRNA-485 Modulates the TGF-β/ Smads Signaling Pathway in Chronic Asthmatic Mice by Targeting Smurf2.

Chronic respiratory conditions continue to plague millions of people worldwide. We aimed to elucidate the detailed mechanisms of microRNA-485 (miR-485) in airway smooth muscle cell (ASMC) proliferation and apoptosis in chronic asthmatic mice. A mouse model of chronic asthma was established. Ovalbumin was used to induce chronic asthma in the mice. The levels of transforming growth factor β (TGF-β), interleukin (IL)-4, IL-5, IL-13 and IL-17 in bronchoalveolar lavage fluid in mice were measured by enzyme-linked immunoassays (ELISAs). ASMCs were transfected with miR-485 mimic, miR-485 inhibitor and siRNA-Smurf2. The reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analyses were applied to detect the mRNA and protein levels of Smurf2, α-SMA, TGF-β1 and decapentaplegic homolog (Smads). The MTT assay was utilized for cell proliferation, while flow cytometry was conducted to assess cell cycle distribution and apoptosis. Lower expression of miR-485 and higher expression levels of TGF-β1, IL-4, IL-5, IL-13 and IL-17 were detected in mice with chronic asthma. Smurf2 was identified as the target gene of miR-485. Upregulation of miR-485 mimic and downregulation of Smurf2 decreased expression levels of Smurf2, α-SMA, TGF-β1 and Smad3, inhibited cell proliferation and increased apoptosis, while contrary results were observed in ASMCs transfected with miR-485 inhibitor. Overexpressed miR-485 inhibits cell proliferation and promotes apoptosis of ASMCs through the Smurf2-mediated TGF-β/Smads signaling pathway in mice with chronic asthma.

Wang J ，Li HY ，Wang HS ，Su ZB ... -  《-》

MicroRNA-133a alleviates airway remodeling in asthtama through PI3K/AKT/mTOR signaling pathway by targeting IGF1R.

Asthma is characterized by chronic inflammation, and long-term chronic inflammation leads to airway remodeling. But the potential regulatory mechanism of airway remodeling is not clearly understood, and there is still no effective way to prevent airway remodeling. Present studies have confirmed the role of microRNAs (miRNAs) in the development of disease, which is known as suppressing translation or degradation of messenger RNA (mRNA) at the posttranscriptional stage. In this study, we described the role of miRNA-133a in asthma and demonstrated it in regulating airway remodeling of asthma through the phosphoinositide 3 kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway by targeting IGF-1 receptor (IGF1R). IGF1R helps in mediating the intracellular signaling cascades. Asthmatic mice models were established by sensitization and Ovalbumin challenge. Adenovirus transfer vector carrying miR-133a or miR-133a sponge sequence was used to build the overexpression or downexpression of miR-133a modeling. Real-time polymerase chain reaction and Western blot were used to determine the alterations in the expression of miR-133a and mRNAs and their corresponding proteins. Results showed that miR-133a was downregulated in asthma. Upregulation of miR-133a expression in airway smooth muscle cells in vivo and in vitro could inhibit the activation of PI3K/AKT/mTOR pathway, and reduce the expression of α-smooth muscle actin (α-SMA), indicating that airway remodeling was inhibited. Functional studies based on luciferase reporter revealed miR-133a as a direct target of IGF1R mRNA. In conclusion, these data suggested that miR-133a regulated the expression of α-SMA through PI3K/AKT/mTOR signaling by targeting IGF1R. miR-133a plays a key role in airway remodeling of asthma and may serve as a potential therapeutic target for managing asthmatic airway remodeling.

Shao Y ，Chong L ，Lin P ，Li H ，Zhu L ，Wu Q ，Li C ... -  《-》

MicroRNA-142 Inhibits Proliferation and Promotes Apoptosis in Airway Smooth Muscle Cells During Airway Remodeling in Asthmatic Rats via the Inhibition of TGF-β -Dependent EGFR Signaling Pathway.

Asthma is a heterogeneous disease characterized by chronic airway inflammation resulting from airway hyper-responsiveness to diverse stimuli. In this study, we investigated whether microRNA-142 (miR-142) expression affects proliferation and apoptosis in airway smooth muscle cells (ASMCs) during airway remodeling in asthmatic rats. Thirty six Wistar rats were randomly classified into a control group and an model group. miR-142 mimics and inhibitors were constructed, and ASMCs were transfected using liposomes according to the following groups: blank, negative control (NC), miR-142 mimics, miR-142 inhibitors, si-TGF-β and miR-142 inhibitors + si-TGF-β. We verified that miR-142 targets TGF-β using a dual-luciferase reporter assay. The expression levels of miR-142, TGF-β, EGFR and apoptosis signaling pathway-related genes were determined using RT-qPCR and western blotting. Changes in cell proliferation, cell cycle progression and apoptosis were analyzed using MTT assays and flow cytometry. Rats with asthma had higher expression levels of EGFR and Akt and lower miR-142 levels. miR-142 was negatively correlated with TGF-β expression. In ASMCs, the expression of TGF-β, EGFR, Akt, phosphorylated-Akt (p-Akt), Bcl-2 and Bcl-xl and the rate of early apoptosis were decreased while expression of Bax and p21 and the proliferation rate were elevated with the upregulation of miR-142. The opposite results were observed with the downregulation of miR-142. Finally, the proliferative rate was decreased while the apoptosis rate was increased and expression levels of EGFR, Akt, p-Akt, Bcl-2 and Bcl-xl were reduced while Bax and p21 were elevated in the ASMCs transfected with miR-142 inhibitors and si-TGF-β. The results of our study suggest that miR-142 inhibits proliferation and promotes apoptosis in ASMCs during airway remodeling in asthmatic rats by inhibiting TGF-β expression via a mechanism involving the EGFR signaling pathway.

Wang J ，Wang HS ，Su ZB 《-》