Amiodarone induces epithelial-mesenchymal transition in A549 cells via activation of TGF-β1

Structural Modification and Optimisation of Hyperoside Oriented to Inhibit TGF-β-Induced EMT Activity in Alveolar Epithelial Cells

Pulmonary fibrosis (PF) is a disease characterised by diffuse nonspecific alveolar inflammation with interstitial fibrosis, which clinically manifests as dyspnoea and a significant decline in lung function. Many studies have shown that the epithelial-mesenchymal transition (EMT) plays a pivotal role in the pathogenesis of pulmonary fibrosis. Based on our previous findings, hypericin (Hyp) can effectively inhibit the process of the EMT to attenuate lung fibrosis. Therefore, a series of hyperoside derivatives were synthesised via modifying the structure of hyperoside, and subsequently evaluated for A549 cytotoxicity. Among these, the pre-screening of eight derivatives inhibits the EMT. In this study, we evaluated the efficacy of Z6, the most promising hyperoside derivative, in reversing TGF-β1-induced EMTs and inhibiting the EMT-associated migration of A549 cells. After the treatment of A549 cells with Z6 for 48 h, RT-qPCR and Western blot results showed that Z6 inhibited TGF-β1-induced EMTs in epithelial cells by supressing morphological changes in A549 cells, up-regulating E-cadherin (p < 0.01, p < 0.001), and down-regulating Vimentin (p < 0.01, p < 0.001). This treatment significantly reduced the mobility of transforming growth factor β1 (TGF-β1)-stimulated cells (p < 0.001) as assessed by wound closure, while increasing the adhesion rate of A549 cells (p < 0.001). In conclusion, our results suggest that hyperoside derivatives, especially compound Z6, are promising as potential lead compounds for treating pulmonary fibrosis, and therefore deserve further investigation.

Omeprazole induces profibrotic gene expression in rat kidney: implication of TGF-β/Smad signaling pathway

Proton pump inhibitors (PPIs) are one of the most commonly prescribed medications. However, PPI usage is linked to a higher risk of both acute and chronic renal damage by mechanisms not entirely known. The present study demonstrates that omeprazole (10 mg/kg body weight, i.p.) causes TGF-β/Smad signaling activation and subsequent expression of the profibrotic genes CTGF and TIMP-1 in rat kidney. Increased production of CTGF and TIMP-1 accompany activation of the TGF-β/Smad signaling cascade. However, simultaneous treatment of omeprazole and the TGF-β inhibitor, disitertide (P144) (1 mg/kg body weight i.p.) suppresses the TGF-β/Smad signaling pathway and subsequent production of CTGF and TIMP-1. Additionally, TGF-β level in rat kidney was highly reduced in animals treated with the ROS (reactive oxygen species) scavenger, N-acetyl cysteine (NAC) (100 mg/kg body weight i.p.) before omeprazole administration. Furthermore, the reduction in SOD activity brought by omeprazole was returned to the normal level in those animals. However, MDA level increased by omeprazole was highly reduced in the presence of NAC. Collectively, the current findings demonstrate that omeprazole has the ability to promote the expression of the profibrotic genes CTGF and TIMP-1 in a ROS and TGF-β dependent manner. The present study suggests the co-use of ROS scavenger to improve the therapeutic use of the PPI omeprazole.

MALAT1-miR-30c-5p-CTGF/ATG5 axis regulates silica-induced experimental silicosis by mediating EMT in alveolar epithelial cells

Epithelial-mesenchymal transdifferentiation of alveolar type Ⅱ epithelial cells is a vital source of pulmonary myofibroblasts, and myofibroblasts formation is recognized as an important phase in the pathological process of silicosis. miR-30c-5p has been determined to be relevant in the activation of the epithelial-mesenchymal transition (EMT) in numerous disease processes. However, elucidating the role played by miR-30c-5p in the silicosis-associated EMT process remains a great challenge. In this work, based on the establishment of mouse silicosis and A549 cells EMT models, miR-30c-5p was interfered with in vivo and in vitro models to reveal its effects on EMT and autophagy. Moreover, metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), connective tissue growth factor (CTGF), autophagy-related gene 5 (ATG5), and autophagy were further interfered with in the A549 cells models to uncover the possible molecular mechanism through which miR-30c-5p inhibits silicosis associated EMT. The results demonstrated the targeted binding of miR-30c-5p to CTGF, ATG5, and MALAT1, and showed that miR-30c-5p could prevent EMT in lung epithelial cells by acting on CTGF and ATG5-associated autophagy, thereby inhibiting the silicosis fibrosis process. Furthermore, we also found that lncRNA MALAT1 might competitively absorb miR-30c-5p and affect the EMT of lung epithelial cells. In a word, interfering with miR-30c-5p and its related molecules (MALAT1, CTGF, and ATG5-associated autophagy) may provide a reference point for the application of silicosis intervention-related targets.

Role of integrin α2 in methotrexate-induced epithelial-mesenchymal transition in alveolar epithelial A549 cells

Methotrexate (MTX) is widely used to treat various diseases. However, it induces adverse reactions like serious lung injury, including pulmonary fibrosis. Increasing evidence suggests that epithelial-mesenchymal transition (EMT) in injured alveolar epithelium contributes to the development of the pathophysiological state of the lung. We demonstrated that MTX induced EMT in cultured alveolar epithelial cell lines. Integrin-mediated signaling is considered a significant factor in recognizing the EMT process. However, the relationship between MTX-induced EMT and integrin family members is poorly understood. In the present study, we aimed to clarify the role of integrin in MTX-induced EMT in A549 and NCI-H1299 (H1299) cells by focusing on the integrin alpha 2 (ITGA2) subunit, selected based on our microarray analysis. MTX treatment for 72 h significantly increased the mRNA and cell surface expression of ITGA2 in both cell lines. However, this upregulation by MTX was suppressed by co-treatment with SB431542 and folic acid, which are inhibitors of MTX-induced EMT in A549 cells. The mRNA expression levels of EMT-related genes were more affected in the MTX-treated A549 cells with high ITGA2 expression than in those with low ITGA2 expression. Finally, E7820, an ITGA2 inhibitor, suppressed MTX-induced EMT-related phenotypic changes, such as morphology and mRNA and protein expression of α-smooth muscle actin, a representative EMT marker. These findings suggest that ITGA2 may play a key role in MTX-induced EMT in alveolar epithelial cells.

Role of Mesenchymal Stem Cells and Extracellular Vesicles in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial fibrotic disease that leads to disability and death within 5 years of diagnosis. Pulmonary fibrosis is a disease with a multifactorial etiology. The concept of aberrant regeneration of the pulmonary epithelium reveals the pathogenesis of IPF, according to which repeated damage and death of alveolar epithelial cells is the main mechanism leading to the development of progressive IPF. Cell death provokes the migration, proliferation and activation of fibroblasts, which overproduce extracellular matrix, resulting in fibrotic deformity of the lung tissue. Mesenchymal stem cells (MSCs) and extracellular vesicles (EVs) are promising therapies for pulmonary fibrosis. MSCs, and EVs derived from MSCs, modulate the activity of immune cells, inhibit the expression of profibrotic genes, reduce collagen deposition and promote the repair of damaged lung tissue. This review considers the molecular mechanisms of the development of IPF and the multifaceted role of MSCs in the therapy of IPF. Currently, EVs-MSCs are regarded as a promising cell-free therapy tool, so in this review we discuss the results available to date of the use of EVs-MSCs for lung tissue repair.

Vincristine Promotes Transdifferentiation of Fibroblasts Into Myofibroblasts via P38 and ERK Signal Pathways

Background: Vincristine (VCR) is used in the clinic as an anti-tumor drug. VCR can cause pulmonary fibrosis (PF), leading to respiratory failure. The transformation of fibroblasts into myofibroblasts may play a key role in PF. The present study attempted to reveal the molecular mechanism of VCR-induced PF and the possible involvement of the mitogen-activated protein kinase (MAPK) signaling pathway.

Methods: Human embryonic lung fibroblasts (HELFs) were treated with different concentrations of VCR. Inhibitors of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 MAPK were added to HELFs. Cell proliferation state was assessed using cell counting kit-8 and by directly counting the number of cells. The expressions of vimentin and α-smooth muscle actin (α-SMA) were investigated using western blot and immunofluorescence analyses. Activation of ERK and P38 was estimated by the expression of phosphorylated p38 MAPK (p-p38), p38 MAPK, phosphorylated ERK1/2 (p-ERK1/2) and ERK1/2 using western blot analysis. Enzyme-linked immunosorbent assay was used to estimate the level of collagen I in cell culture supernatants.

Results: Results showed that VCR promoted cellular proliferation, secretion of collagen I and the expression of vimentin and α-SMA. High expression of p-p38 and p-ERK1/2 was associated with the activation of the MAPK signaling pathway. MAPK inhibitors SB203580 and PD98059 suppressed the expression of the above proteins.

Conclusion: Our study revealed that VCR could promote the differentiation of fibroblasts into myofibroblasts by regulating the MAPK signal pathway, which may be a promising way to treat VCR-induced PF.

Aminophylline modulates the permeability of endothelial cells via the Slit2-Robo4 pathway in lipopolysaccharide-induced inflammation

Sepsis and septic shock are the main cause of mortality in intensive care units. The prevention and treatment of sepsis remains a significant challenge worldwide. The endothelial cell barrier plays a critical role in the development of sepsis. Aminophylline, a non-selective phosphodiesterase inhibitor, has been demonstrated to reduce endothelial cell permeability. However, little is known regarding the role of aminophylline in regulating vascular permeability during sepsis, as well as the potential underlying mechanisms. In the present study, the Slit2/Robo4 signaling pathway, the downstream protein, vascular endothelial (VE)-cadherin and endothelial cell permeability were investigated in a lipopolysaccharide (LPS)-induced inflammation model. It was indicated that, in human umbilical vein endothelial cells (HUVECs), LPS downregulated Slit2, Robo4 and VE-cadherin protein expression levels and, as expected, increased endothelial cell permeability in vitro during inflammation. After administration of aminophylline, the protein expression levels of Slit2, Robo4 and VE-cadherin were upregulated and endothelial cell permeability was significantly improved. These results suggested that the permeability of endothelial cells could be mediated by VE-cadherin via the Slit2/Robo4 signaling pathway. Aminophylline reduced endothelial permeability in a LPS-induced inflammation model. Therefore, aminophylline may represent a promising candidate for modulating vascular permeability induced by inflammation or sepsis.

miR-184 targets TP63 to block idiopathic pulmonary fibrosis by inhibiting proliferation and epithelial-mesenchymal transition of airway epithelial cells

Epithelial-to-mesenchymal transition (EMT) of epithelium and airway epithelial cell proliferation disorder are key events in idiopathic pulmonary fibrosis (IPF) pathogenesis. During EMT, epithelial cell adhesion molecules (EpCAM, such as E-cadherin) are downregulated, cytokeratin cytoskeletal transforms into vimentin-based cytoskeleton, and the epithelial cells acquire mesenchymal morphology. In the present study, we show abnormal upregulation of tumor protein p63 (TP63) and downregulation of miR-184 in IPF. Transforming growth factor beta 1 (TGF-β1) stimulation of BEAS-2B and A549 cell lines significantly increased the protein levels of Tp63, alpha-smooth muscle actin (α-SMA), and vimentin, but decreased EpCAM protein levels, and promoted viability of both BEAS-2B and A549 cell lines. TP63 knockdown in BEAS-2B and A549 cell lines significantly attenuated above-described TGF-β1-induced fibrotic changes. miR-184 targeted TP63 3'-UTR to inhibit Tp63 expression. miR-184 overexpression within BEAS-2B and A549 cell lines also attenuated TGF-β1-induced fibrotic changes. miR-184 overexpression attenuated bleomycin-induced pulmonary fibrosis in mice. Moreover, TP63 overexpression aggravated TGF-β1-stimulated fibrotic alterations within BEAS-2B and A549 cells and significantly reversed the effects of miR-184 overexpression, indicating miR-184 relieves TGF-β1-stimulated fibrotic alterations within BEAS-2B and A549 cells by targeting TP63, while TP63 overexpression reversed miR-184 cellular functions. In conclusion, the miR-184/TP63 axis modulates the TGF-β1-induced fibrotic alterations in epithelial cell lines and bleomycin-induced pulmonary fibrosis in mice. Therefore, these results confirm that the miR-184/TP63 axis is involved in IPF progression.

Association of cell cycle arrest with anticancer drug-induced epithelial-mesenchymal transition in alveolar epithelial cells

Many drugs exert serious cytotoxic effects on pulmonary tissues. Although several reports have shown an association of epithelial-mesenchymal transition (EMT) with anticancer drug-induced lung injury, mechanisms of these effects are poorly understood. In the present study, we evaluated mechanisms of anticancer drug-induced EMT, with a focus on involvement of cell cycle arrest. We found that methotrexate (MTX) altered mRNA expression levels of many genes as determined by microarray analysis. Gene set enrichment analysis revealed that cell cycle arrest pathways may be associated with MTX-induced EMT. In addition, thymidine (THY) and nocodazole (NOC), which induce cell cycle arrest at S-phase and G2/M-phase, increased mRNA expression levels of α-smooth muscle actin (SMA), an EMT marker. Furthermore, α-SMA protein expression in cells arrested at S- and G2/M-phases by MTX and paclitaxel (PTX) was significantly higher than that in cells at G1. Notably, co-treatment of cells with THY or NOC and EMT-inducing anticancer drugs did not result in additional upregulation of α-SMA mRNA expression. These findings suggested that cell cycle arrest may be closely associated with anticancer drug-induced EMT in alveolar epithelial cells.