Effect of miR-506-3p on Proliferation and Apoptosis of Airway Smooth Muscle Cells in Asthmatic Mice by Regulating CCL2 Gene Expression and Mediating TLR4/NF-κB Signaling Pathway Activation

Noncoding RNAs in asthmatic airway smooth muscle cells

Asthma is a complex and heterogeneous airway disease caused by genetic, environmental and epigenetic factors treated with hormones and biologics. Irreversible pathological changes to airway smooth muscle cells (ASMCs) such as hyperplasia and hypertrophy can occur in asthmatic patients. Determining the mechanisms responsible is vital for preventing such changes. In recent years, noncoding RNAs (ncRNAs), especially microRNAs, long noncoding RNAs and circular RNAs, have been found to be associated with abnormalities of the ASMCs. This review highlights recent ncRNA research into ASMC pathologies. We present a schematic that illustrates the role of ncRNAs in pathophysiological changes to ASMCs that may be useful in future research in diagnostic and treatment strategies for patients with asthma.

Combined Epimedii Folium and Ligustri Lucidi Fructus with dexamethasone alleviate the proliferation of airway smooth muscle cells by regulating apoptosis/autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM) theory believes kidney deficiency is the root cause of chronic refractory asthma with pathological changes of airway remodeling. Our previous experiments confirmed that the combination of Epimedii Folium and Ligustri Lucidi Fructus (ELL) with the effect of nourishing Yin and Yang of the kidney could improve the pathological changes of airway remodeling in asthmatic rats, but the specific mechanism remains unclear.

AIM OF THE STUDY

This research was designed to reveal the synergy of ELL and dexamethasone (Dex) in the proliferation, apoptosis, and autophagy of airway smooth muscle cells (ASMCs).

MATERIALS AND METHODS

Primary cultures of ASMCs from rats were prepared and induced with histamine (Hist), Z-DEVD-FMK (ZDF), rapamycin (Rap), or 3-Methyladenine (3-MA) at generation 3-7 for 24 or 48 h. Subsequently, the cells were treated with Dex, ELL, and ELL&Dex for 24 or 48 h. The effect of various concentrations of inducers and drugs on cell viability was detected by Methyl Thiazolyl Tetrazolium (MTT) assay, cell proliferation was tested using immunocytochemistry (ICC) by detecting Ki67 protein, cell apoptosis was measured by Annexin V-FITC/PI assay and Hoechst nuclear staining, cell ultrastructure was observed by transmission electron microscopy (TEM), and immunofluorescence (IF), western blot (WB) combined with quantitative real-time PCR (qPCR) were used for measuring autophagy and apoptosis-related genes including protein 53 (P53), cysteinyl aspartate-specific proteinase (Caspase)-3, microtubule-associated protein 1 light chain 3 (LC3), Beclin-1, mammalian target of rapamycin (mTOR) and p-mTOR.

RESULTS

In ASMCs, Hist and ZDF promoted cell proliferation, significantly decreased Caspase-3 protein expression, and up-regulated Beclin-1 levels; Dex alone and in combination with ELL promoted Beclin-1, Caspase-3, and P53 expression, enhancing autophagy activity and apoptosis in Hist and ZDF-induced AMSCs. In contrast, Rap inhibited cell viability, increased Caspase-3, P53, Beclin-1, and LC3-II/I and decreased the levels of mTOR and p-mTOR with promoting apoptosis and autophagy; ELL or ELL&Dex reduced P53, Beclin-1, and LC3-II/I to down-regulate apoptosis and the excessive autophagic state of ASMCs induced by Rap. In the 3-MA model, cell viability and autophagy were reduced; ELL&Dex significantly upgraded the expression of Beclin-1, P53, and Caspase-3 and promoted apoptosis and autophagy of ASMCs.

CONCLUSIONS

These results suggest that ELL combined with Dex may regulate the proliferation of ASMCs by promoting apoptosis and autophagy and be a potential medicine for the treatment of asthma.

The TLR4/NF-κB signaling pathway-mediated type 2 skewing of T helper cell in cough variant asthma was counteracted by ethanol extract of Anacyclus pyrethrum root

Type 2 T helper (Th2) cells-mediated immune response plays a pivotal role in the pathogenesis of cough variant asthma (CVA), and this study aims to determine the effect and mechanism of ethanol extract of Anacyclus pyrethrum root (EEAP) on regulating Th2 response in CVA. Peripheral blood mononuclear cells (PBMCs) collected from patients with CVA, and naive CD4⁺T cells induced by Th2-polarizing medium were administrated with EEAP. Interestingly, through conducting flow cytometry and enzyme linked immunosorbent assay method, we found that EEAP significantly alleviated Th2 skewing and increased Th1 response in these two kinds of cells. Results of western blot assay and quantitative reverse transcription PCR displayed that EEAP suppressed the expression of TLR4, total NF-κB p65, nuclear NF-κB p65 and the downstream genes. Subsequently, we proved that TLR4 antagonist E5564 played a similar improvement role to EEAP in Th1/Th2 imbalance, while combination of TLR4 agonist LPS and EEAP abolished the inhibitory effect of EEAP on Th2 polarization in Th2-induced CD4⁺T cells. Finally, CVA models induced by ovalbumin and capsaicin were established in cavies, and data showed that EEAP also improved Th1/Th2 imbalance in CVA in vivo, manifested in the increase of IL4⁺CD4⁺T cell ratio, Th2 cytokines (IL-4, IL-5, IL-6 and IL-13) and the decrease of Th1 cytokines (IL-2 and IFN-γ). Co-treatment of LPS and EEAP counteracted the inhibition of EEAP on Th2 response in CVA model cavies. Moreover, we found that EEAP mitigated airway inflammation and hyper-responsiveness in vivo, which was abolished by the combined application of LPS. In a word, EEAP restores Th1/Th2 balance in CVA through restraining the TLR4/NF-кB signaling pathway. This study may contribute to the clinical application of EEAP in CVA-related disease.

ITGB4 deficiency in airway epithelia enhances HDM-induced airway inflammation through hyperactivation of TLR4 signaling pathway

Airway epithelial cells (AECs) are the first cell barrier of the respiratory system against external stimuli that play a critical role in the development of asthma. It is known that AECs play a key role in asthma susceptibility and severity. ITGB4 is a downregulated adhesion molecule in the airway epithelia of asthma patients, which was involved in the exaggerated lung inflammation after allergy stimulation. Toll-like receptor 4 (TLR4) in AECs has also been shown to play a crucial role in the development of lung inflammation in asthma patients. However, the specific intrinsic regulatory mechanism of TLR4 in AECs are still obscure. In this article, we demonstrated that ITGB4 deficiency in AECs enhances HDM-induced airway inflammation through hyperactivation of the TLR4 signaling pathway, which is mediated by inhibition of FYN phosphorylation. Moreover, TLR4-antagonist treatment or blockade of FYN can inhibit or exaggerate lung inflammation in HDM-stressed ITGB4-deficient mice, separately. Together, these results demonstrated that ITGB4 deficiency in AECs enhances HDM-induced lung inflammatory response through the ITGB4-FYN-TLR4 axis, which may provide new therapeutic approaches for the management of lung inflammation in asthma.

MiR-506 targets polypyrimidine tract-binding protein 1 to inhibit airway inflammatory response and remodeling via mediating Wnt/β-catenin signaling pathway

BACKGROUND

Airway remodeling, which contributes to the clinical course of childhood asthma, occurs due to airway inflammation and is featured by anomalous biological behaviors of airway smooth muscle cells (ASMCs). microRNA (miRNA) plays an essential role in the etiopathogenesis of asthma.

OBJECTIVE

This research was aimed to characterize miR-506 in asthma and uncover potential regulatory machinery.

MATERIAL AND METHODS

The asthmatic cell model was established by treating ASMCs with transforming growth factor-beta1 (TGF-β1) and assessed by the levels of interleukin (IL)-1β and interferon gamma (IFN-γ). Using real-time quantitative polymerase chain reaction, mRNA expression of miR-506 and polypyrimidine tract-binding protein 1 (PTBP1) was measured. Cell counting kit-8 and Transwell migration tests were used for estimating the capacity of ASMCs to proliferate and migrate. Luciferase reporter assay was used to corroborate whether miR-506 was directly bound to PTBP1. Expression of PTBP1, collagen I and III, and essential proteins of the wingless-related integration (Wnt)/β-catenin pathway (β-catenin, c-MYC and cyclin D1) was accomplished by Western blot analysis. The involvement of Wnt/β-catenin signaling in asthma was confirmed by Wnt signaling pathway inhibitor (IWR-1).

RESULTS

miR-506 was poorly expressed in asthmatic tissues and cell model. Functionally, overexpression of miR-506 reduced aberrant proliferation, migration, inflammation and collagen deposition of ASMCs triggered by TGF-β1. Mechanically, miR-506 directly targeted the 3' untranslated region (3-UTR) of PTBP1 and had a negative regulation on PTBP1 expression. Moreover, overexpression of miR-506 suppressed the induction of Wnt/β-catenin pathway. The administration of IWR-1 further validated negative correlation between miR-506 and the Wnt/β-catenin pathway in asthma.

CONCLUSION

Our data indicated that targeting miR-506/PTBP1/Wnt/β-catenin axis might point in a helpful direction for treating asthma in children.

The Crosstalk between FcεRI and Sphingosine Signaling in Allergic Inflammation

Sphingolipid molecules have recently attracted attention as signaling molecules in allergic inflammation diseases. Sphingosine-1-phosphate (S1P) is synthesized by two isoforms of sphingosine kinases (SPHK 1 and SPHK2) and is known to be involved in various cellular processes. S1P levels reportedly increase in allergic inflammatory diseases, such as asthma and anaphylaxis. FcεRI signaling is necessary for allergic inflammation as it can activate the SPHKs and increase the S1P level; once S1P is secreted, it can bind to the S1P receptors (S1PRs). The role of S1P signaling in various allergic diseases is discussed. Increased levels of S1P are positively associated with asthma and anaphylaxis. S1P can either induce or suppress allergic skin diseases in a context-dependent manner. The crosstalk between FcεRI and S1P/SPHK/S1PRs is discussed. The roles of the microRNAs that regulate the expression of the components of S1P signaling in allergic inflammatory diseases are also discussed. Various reports suggest the role of S1P in FcεRI-mediated mast cell (MC) activation. Thus, S1P/SPHK/S1PRs signaling can be the target for developing anti-allergy drugs.

Knockdown of circ_0003928 ameliorates high glucose-induced dysfunction of human tubular epithelial cells through the miR-506-3p/HDAC4 pathway in diabetic nephropathy

Background

Previous data have indicated the importance of circular RNA (circRNA) in the pathogenesis of diabetic nephropathy (DN). The study is designed to investigate the effects of circ_0003928 on oxidative stress and apoptosis of high glucose (HG)-treated human tubular epithelial cells (HK-2) and the underlying mechanism.

Methods

The DN cell model was established by inducing HK-2 cells using 30 mmol/L D-glucose. RNA expression of circ_0003928, miR-506-3p and histone deacetylase 4 (HDAC4) was detected by quantitative real-time polymerase chain reaction. Cell viability and proliferation were investigated by cell counting kit-8 and 5-Ethynyl-29-deoxyuridine (EdU) assays, respectively. Oxidative stress was evaluated by commercial kits. Caspase 3 activity and cell apoptotic rate were assessed by a caspase 3 activity assay and flow cytometry analysis, respectively. Protein expression was detected by Western blotting analysis. The interactions among circ_0003928, miR-506-3p and HDAC4 were identified by dual-luciferase reporter and RNA pull-down assays.

Results

Circ_0003928 and HDAC4 expression were significantly upregulated, while miR-506-3p was downregulated in the serum of DN patients and HG-induced HK-2 cells. HG treatment inhibited HK-2 cell proliferation, but induced oxidative stress and cell apoptosis; however, these effects were reversed after circ_0003928 depletion. Circ_0003928 acted as a miR-506-3p sponge, and HDAC4 was identified as a target gene of miR-506-3p. Moreover, the circ_0003928/miR-506-3p/HDAC4 axis regulated HG-induced HK-2 cell dysfunction.

Conclusion

Circ_0003928 acted as a sponge for miR-506-3p to regulate HG-induced oxidative stress and apoptosis of HK-2 cells through HDAC4, which suggested that circ_0003928 might be helpful in the therapy of DN.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00679-y.

Non-coding RNA-based regulation of inflammation

Inflammation is a multifactorial process and various biological mechanisms and pathways participate in its development. The presence of inflammation is involved in pathogenesis of different diseases such as diabetes mellitus, cardiovascular diseases and even, cancer. Non-coding RNAs (ncRNAs) comprise large part of transcribed genome and their critical function in physiological and pathological conditions has been confirmed. The present review focuses on miRNAs, lncRNAs and circRNAs as ncRNAs and their potential functions in inflammation regulation and resolution. Pro-inflammatory and anti-inflammatory factors are regulated by miRNAs via binding to 3'-UTR or indirectly via affecting other pathways such as SIRT1 and NF-κB. LncRNAs display a similar function and they can also affect miRNAs via sponging in regulating levels of cytokines. CircRNAs mainly affect miRNAs and reduce their expression in regulating cytokine levels. Notably, exosomal ncRNAs have shown capacity in inflammation resolution. In addition to pre-clinical studies, clinical trials have examined role of ncRNAs in inflammation-mediated disease pathogenesis and cytokine regulation. The therapeutic targeting of ncRNAs using drugs and nucleic acids have been analyzed to reduce inflammation in disease therapy. Therefore, ncRNAs can serve as diagnostic, prognostic and therapeutic targets in inflammation-related diseases in pre-clinical and clinical backgrounds.