3605

IL17A

Severe asthma is a chronic airway disease characterized by the Th2/Th17-polarized inflammation along with permanent airway remodeling. Despite past extensive studies, the exact role for Th2 and Th17 cytokines in asthmatic pathoetiology, particularly in the pathogenesis of bronchial epithelial-mesenchymal transition (EMT), is yet to be fully addressed. We herein conducted studies in 16-HBE cells and demonstrated that Th2-derived IL-4 and Th17-derived IL-17A provide a chronic inflammatory milieu that favors TGF-beta1 to induce bronchial EMT. A synergic action was noted between TGF-beta1, IL-4 and IL-17A in terms of induction of EMT. IL-4 and IL-17A synergized with TGF-beta1 to induce epithelial cells re-entering cell cycle, and to promote epithelial to mesenchymal morphological transistion, and by which they enhanced the capacity of TGF-beta1 to suppress E-cadherin expression, and to induce a-SMA expression in epithelial cells. Mechanistic studies revealed that this synergic action is coordinated by the regulation of ERK1/2 activity. Our results not only provide a novel insight into the understanding of the mechanisms underlying airway remodeling in asthmatic condition, but also have the potential for developing more effective therapeutic strategies against severe asthmatics in clinical settings.

Primary biliary cirrhosis (PBC) is an autoimmune chronic liver disease with worldwide increasing morbidity. However, the etiology of PBC is still unclear. Recently, the epithelial-mesenchymal transition (EMT) and interleukin-17A (IL-17A), a pro-inflammatory cytokine, were proposed to be involved in the pathogenesis of PBC. Therefore, in this study, we aimed to clarify the roles of IL-17A and/or EMT in the onset of PBC. The results showed that the median serum IL-17A level was significantly higher in 29 PBC patients (average course of 40.69 months) than that of 11 healthy controls. The intrahepatic biliary epithelial cells (IBECs), the major target of destruction in PBC, underwent EMT in PBC patients. The immunohistochemical analysis revealed that the protein levels of IL-17A receptor were increased in IBECs and the IL-17A protein was accumulated around the IBECs in the PBC patients. These results imply that the IL-17A-mediated signaling and EMT of intrahepatic biliary epithelial cells (IBEC-EMT) are key pathogenic processes of PBC. To study the association between IL-17A and IBECs-EMT, we then examined if IL-17A induced EMT using a human cell line of IBECs (HIBECs). After the treatment with IL-17A for 48 h, HIBECs changed into bipolar cells with a fibroblastic morphology. Additionally, the results of real-time PCR and Western blot analyses demonstrated that IL-17A up-regulated the expression of a mesenchymal marker vimentin and down-regulated the expression of an epithelial marker E-cadherin in HIBECs in the dose- and time-dependent manners. These results suggest that IL-17A may play an important role in the IBECs-EMT.

Idiopathic pulmonary fibrosis (IPF) is a chronic and usually progressive lung disease and the epithelial-mesenchymal transition (EMT) may play an important role in the pathogenesis of pulmonary fibrosis. IL-17 is a proinflammatory cytokine which promotes EMT profiles in lung inflammatory diseases. In this study, we investigated the effect of IL-17 on EMT in alveolar epithelial cell line A549 and the role of TGFbeta1-Smad and ERK signaling pathways in the process. Morphological observation on the cells was performed under inverted microscope. The mRNA and protein expressions of E-cad and alpha-SMA were detected by quantitative RT-PCR and western blotting. The mRNA and protein expressions of TGF-beta1 were analyzed via quantitative RT-PCR and ELISA. expressions of Smad2/3, p-Smad2/3, ERK1/2, p-ERK1/2 and p-JNK were examined by western blotting. The results indicated that IL-17 can induce A549 cells to undergo morphological changes and phenotypic markers changes, such as down-regulated E-cad expression and up-regulated alpha-SMA expression. Additionally, IL-17 enhanced TGF-beta1 expression and stimulated Smad2/3 and ERK1/2 phosphorylation in A549 cells. However, there were no significant differences in the expression of phosphorylated JNK in A549 cells with or without IL-17 treatment. SB431542 or U0126 treated cells showed inhibited morphological changes and phenotypic markers expression, such as up-regulated E-cad expression and down-regulated alpha-SMA expression. In summary, our results suggest that IL-17 can induce A549 alveolar epithelial cells to undergo EMT via the TGF-beta1 mediated Smad2/3 and ERK1/2 activation.

We previously demonstrated that interleukin-17A (IL-17A) is associated with the progression of hepatocellular carcinoma (HCC). However, its role in the invasion-metastasis cascade of HCC and the efficacy of IL-17A-targeting therapeutics in HCC remain largely unknown. In this study, we found that IL-17A promoted intrahepatic and pulmonary metastasesis of HCC cells in an orthotopic implant model. Moreover, our results showed that IL-17A induced epithelial-mesenchymal transition (EMT) and promoted HCC cell colonization in vitro and in vivo, and the role of IL-17A in invasion-metastasis was dependent on activation of the AKT pathway. Remarkably, combined therapy using both secukinumab and sorafenib has better inhibition on tumour growth and metastasis compared to sorafenib monotherapy. Additionally, the combination of intratumoral IL-17A+ cells and E-cadherin predicted the outcome of patients with HCC at an early stage after hepatectomy based on tissue microarray and immunohistochemistry. In conclusion, our studies reveal that IL-17A induces early EMT and promotes late colonization of HCC metastasis by activating AKT signalling. Secukinumab is a promising candidate for clinical development in combination with sorafenib for the management of HCC.CI - (c) 2018 The Authors. Published by FEBS Press and John Wiley & Sons Ltd.

BACKGROUND: Intestinal fibrosis is a common complication of Crohn's disease (CD). Its exact mechanism is still unclear, and effective treatments to control or reverse the fibrosis process are unavailable. epithelial-mesenchymal transition (EMT) may promote intestinal fibrosis by increasing deposition of extracellular matrix protein. IL-17A is a pro-inflammatory cytokine, and it has been shown as a profibrotic factor as its association with fibrosis of multiple organs was reported. AIMS: To assess the roles of IL-17A and EMT in the initiation and development of intestinal fibrosis and to verify the potential inductive effect of IL-17A on EMT. METHODS: In this study, we evaluated the expression of IL-17A and EMT-related genes in colonic mucosal biopsy tissues of CD patients and control individuals. Then, we examined the changes of EMT-related genes and fibrosis-related genes of IEC-6 cells which cultured for 72 h under increasing concentrations of IL-17A or with TGF-beta1, to verify the potential inductive effect of IL-17A on EMT in vitro. We blocked the IL-17A of the mouse model of TNBS-induced experimental intestinal colitis and fibrosis to further verify the potential inductive effect of IL-17A on EMT in vivo. RESULTS: We found the occurrence of EMT and high-level expression of IL-17A in intestinal mucosa of CD patients. Using IEC-6 cells, we showed that IL-17A may induce EMT in intestinal epithelial cells that come with reduced E-cadherin expression and increased expression of vimentin, snail, and alpha-SMA. We further found that anti-IL-17A treatment alleviated intestinal fibrosis through reducing EMT in mouse intestine. CONCLUSIONS: Our study confirmed the involvement of IL-17A in the development of intestinal fibrosis through inducing EMT.