Smad3-mediated lncRNA HSALR1 enhances the non-classic signalling pathway of TGF-ß1 in human bronchial fibroblasts by binding to HSP90AB1.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is one of the diseases with high mortality and morbidity with complex pathogenesis. Airway remodeling is an unavoidable pathological characteristic. However, the molecular mechanisms of airway remodeling are incompletely defined. METHODS: lncRNAs highly correlated with transforming growth factor beta 1(TGF-ß1) expression were chosen, the lncRNA ENST00000440406 (named HSP90AB1 Assoicated LncRNA 1, HSALR1) was chosen for further functional experiments. Dual luciferase and ChIP assay were used to detect the upstream of HSALR1, transcriptome sequencing, Cck-8, Edu, cell proliferation, cell cycle assay, and WB detection of pathway levels confirmed the effect of HSALR1 on fibroblast proliferation and phosphorylation levels of related pathways. Mice was infected with adeno-associated virus (AAV) to express HSALR1 by intratracheal instillation under anesthesia and was exposure to cigarette smoke, then mouse lung function was performed and the pathological sections of lung tissues were analyzed. RESULTS: Herein, lncRNA HSALR1 was identified as highly correlated with the TGF-ß1 and mainly expressed in human lung fibroblasts. HSALR1 was induced by Smad3 and promoted fibroblasts proliferation. Mechanistically, it could directly bind to HSP90AB1 protein, and acted as a scaffold to stabilize the binding between Akt and HSP90AB1 to promote Akt phosphorylation. In vivo, mice expressed HSALR1 by AAV was exposure to cigarette smoke (CS) for COPD modeling. We found that lung function was worse and airway remodeling was more pronounced in HSLAR1 mice compare to wild type (WT) mice. CONCLUSION: Our results suggest that lncRNA HSALR1 binds to HSP90AB1 and Akt complex component, and enhances activity of the TGF-ß1 smad3-independent pathway. This finding described here suggest that lncRNA can participate in COPD development, and HSLAR1 is a promising molecular target of COPD therapy.

Genetic screening of MMP1 as a potential pathogenic gene in chronic obstructive pulmonary disease.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous syndrome. Airway inflammation and remodeling are the two key processes involved in COPD pathogenesis. However, the key pathogenic genes driving COPD development have not been revealed. This study aims to identify and validate hub gene(s) underlying COPD development through bioinformatics analysis and experimental validation. METHODS: Three lung tissue sequencing datasets of the COPD (including GSE38974, GSE103174, and GSE106986) were analyzed. Further, differentially expressed genes (DEGs) were used to compare patients with COPD with non-COPD individuals, and the Robust Rank Aggregation (RRA) analysis was also performed. Results revealed a series of potential pathogenic genes of COPD. DEGs were subjected to KEGG, GO, and GSEA analyses. The scRNA dataset of human lung tissues (Human Lung Cell Atlas), and human primary airway epithelial cells (GSE134147) were used to identify the cell subtype localization. The qRT-PCR assay was performed in the human lung tissues, COPD mice model, and primary bronchial epithelial cells at the air-liquid interface (ALI) under cigarette smoke extract (CSE) stimulation to verify the expression of the hub genes. LASSO and GLM analysis with the hub genes were performed to identify the most critical gene. RNA-seq was performed after knocking down the critical gene using siRNA in HBECs at ALI. The potential role of the critical gene was confirmed through qRT-PCR, Western blot, and Immunofluorescence (IF) assays. RESULTS: A total of 98 genes were significantly and differently expressed in 3 GEO datasets. The KEGG and GO analyses showed that most of these genes are responsible for inflammation, immunity, and cell proliferation. The core gene set including 15 genes was screened out and consequently, the MMP1 was the most likely responsible for the progression of COPD. Moreover, we confirmed that MMP1 is significantly related to inflammatory effects and cilia function in human bronchial epithelial cells cultured at the air-liquid interface (ALI). CONCLUSION: In summary, we confirmed that inflammation and cell proliferation are potentially critical processes in COPD occurrence and development. A total of 15 potential hub genes were identified among which MMP1 was the most likely gene responsible for the development of COPD. Therefore, MMP1 is a potential molecular target of COPD therapy.

Analysis and Construction of a Competitive Endogenous RNA Regulatory Network of Baicalin-Induced Apoptosis in Human Osteosarcoma Cells.

BACKGROUND: Baicalin is an extract from the traditional Chinese herb Scutellaria baicalensis and has the potential to treat osteosarcoma (OS). However, the transcriptome-level mechanism of baicalin-mediated antitumor effects in OS has not yet been investigated. The aim of this study was to analyze the competitive endogenous RNA (ceRNA) regulatory network involved in baicalin-induced apoptosis of OS cells. METHODS: In this study, CCK-8 and flow cytometry assays were used to detect the antitumor effects of baicalin on human OS MG63 cells. Furthermore, transcriptome sequencing was employed to establish the long noncoding RNA (lncRNA), microRNA (miRNA), and mRNA profiles. RESULTS: Baicalin inhibited MG63 cell proliferation and induced apoptosis. Totals of 58 lncRNAs, 31 miRNAs, and 2136 mRNAs in the baicalin-treated MG63 cells were identified as differentially expressed RNAs compared to those in control cells. Of these, 2 lncRNAs, 3 miRNAs, and 18 mRNAs were included in the ceRNA regulatory network. The differentially expressed RNAs were confirmed by quantitative real-time PCR (qRT-PCR). CONCLUSIONS: By identifying the ceRNA network, our results provide new information about the possible molecular basis of baicalin, which has potential applications in OS treatment.

Long noncoding RNA IL6-AS1 is highly expressed in chronic obstructive pulmonary disease and is associated with interleukin 6 by targeting miR-149-5p and early B-cell factor 1.

Chronic obstructive pulmonary disease is a complex condition with multiple etiologies, including inflammation. We identified a novel long noncoding RNA (lncRNA), interleukin 6 antisense RNA 1 (IL6-AS1), which is upregulated in this disease and is associated with airway inflammation. We found that IL6-AS1 promotes the expression of inflammatory factors, especially interleukin (IL) 6. Mechanistically, cytoplasmic IL6-AS1 acts as an endogenous sponge by competitively binding to the microRNA miR-149-5p to stabilize IL-6 mRNA. Nuclear IL6-AS1 promotes IL-6 transcription by recruiting early B-cell factor 1 to the IL-6 promoter, which increases the methylation of the H3K4 histone and acetylation of the H3K27 histone. We propose a model of lncRNA expression in both the nucleus and cytoplasm that exerts similar effects through differing mechanisms, and IL6-AS1 probably increases inflammation via multiple pathways.

Long Noncoding RNA COPDA1 Promotes Airway Smooth Muscle Cell Proliferation in Chronic Obstructive Pulmonary Disease.

Abnormal expression of long noncoding RNAs (lncRNAs) has been confirmed to be associated with many diseases, including chronic obstructive pulmonary disease (COPD). To gain better understanding of the mechanism of COPD, we investigated the lncRNA and mRNA profiles in the lung tissue of patients with COPD. According to the analysis, one of the significantly different lncRNAs, COPDA1, might participate in the occurrence and development of COPD. Lung tissues were collected from nonsmokers, smokers, or smokers with COPD for RNA sequencing. Bioinformatic analysis and cell experiments were used to define the function of COPDA1, and the effects of COPDA1 on intracellular Ca2+ concentration and cell proliferation were examined after knockdown or overexpression of COPDA1. A number of variations of lncRNAs were found in the comparison of nonsmokers, smokers, and smokers with COPD. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analyses indicated that smoking was involved in the activation of cytokines and the cell cycle, which is associated with COPD. According to the lncRNA-mRNA-coexpressing network and enrichment analysis, COPDAz1 and one of its target genes, MS4A1 (membrane-spanning 4-domains family, subfamily A) were investigated, and we discovered that the expression of MS4A1 was closely associated with lncRNA COPDA1 expression in human bronchial smooth muscle cells (HBSMCs). Further study showed that lncRNA COPDA1 upregulated the expression of MS4A1 to increase store-operated calcium entry in the HBSMCs, resulting in the promotion of the proliferation of smooth muscle cells as well as of airway remodeling. COPDA1 might be involved in the regulation of certain signaling pathways in COPD, might promote the proliferation of HBSMCs, and might also be involved in facilitating airway remodeling.

PM2.5 promotes human bronchial smooth muscle cell migration via the sonic hedgehog signaling pathway.

BACKGROUND: The contribution of airway remodeling in chronic obstructive pulmonary disease (COPD) has been well documented, with airway smooth muscle cell proliferation and migration playing a role in the remodeling process. Here, we aimed to verify the effects of fine particulate matter (PM2.5) on human bronchial smooth muscle cell (HBSMC) migration and to explore the underlying signaling pathways. METHODS: HBSMC apoptosis, proliferation and migration were measured using flow cytometry, cell counting and transwell migration assays, respectively. The role of the hedgehog pathway in cell migration was assessed by western blotting to measure the expression of Sonic hedgehog (Shh), Gli1 and Snail. Furthermore, siRNA was used to knock down Gli1 or Snail expression. RESULTS: PM2.5 induced HBSMC apoptosis in a dose-dependent manner, although certain concentrations of PM2.5 did not induce HBSMC proliferation or apoptosis. Interestingly, cell migration was stimulated by PM2.5 doses far below those that induced apoptosis. Additional experiments revealed that these PM2.5 doses enhanced the expression of Shh, Gli1 and Snail in HBSMCs. Furthermore, PM2.5-induced cell migration and protein expression were enhanced by recombinant Shh and attenuated by cyclopamine. Similar results were obtained by knocking down Gli1 or Snail. CONCLUSIONS: These findings suggest that PM2.5, which may exert its effects through the Shh signaling pathway, is necessary for the migration of HBSMCs. These data define a novel role for PM2.5 in airway remodeling in COPD.

Nicotine-Induced Airway Smooth Muscle Cell Proliferation Involves TRPC6-Dependent Calcium Influx Via α7 nAChR.

BACKGROUND/AIMS: The proliferation of human bronchial smooth muscle cells (HBSMCs) is a key pathophysiological component of airway remodeling in chronic obstructive pulmonary disease (COPD) for which pharmacotherapy is limited, and only slight improvements in survival have been achieved in recent decades. Cigarette smoke is a well-recognized risk factor for COPD; however, the pathogenesis of cigarette smoke-induced COPD remains incompletely understood. This study aimed to investigate the mechanisms by which nicotine affects HBSMC proliferation. METHODS: Cell viability was assessed with a CCK-8 assay. Proliferation was measured by cell counting and EdU immunostaining. Fluorescence calcium imaging was performed to measure intracellular Ca2+ concentration ([Ca2+]i). RESULTS: The results showed that nicotine promotes HBSMC proliferation, which is accompanied by elevated store-operated calcium entry (SOCE), receptor-operated calcium entry (ROCE) and basal [Ca2+]i in HBSMCs. Moreover, we also confirmed that canonical transient receptor potential protein 6 (TRPC6) and α7 nicotinic acetylcholine receptor (α7 nAChR) are involved in nicotine-induced upregulation of cell proliferation. Furthermore, we verified that activation of the PI3K/Akt signaling pathway plays a pivotal role in nicotine-enhanced proliferation and calcium influx in HBSMCs. Inhibition of α7 nAChR significantly decreased Akt phosphorylation levels, and LY294002 inhibited the protein expression levels of TRPC6. CONCLUSION: Herein, these data provide compelling evidence that calcium entry via the α7 nAChR-PI3K/Akt-TRPC6 signaling pathway plays an important role in the physiological regulation of airway smooth muscle cell proliferation, representing an important target for augmenting airway remodeling.