scholarly journals BRD4 mediates NF-κB-dependent epithelial-mesenchymal transition and pulmonary fibrosis via transcriptional elongation

2016 ◽  
Vol 311 (6) ◽  
pp. L1183-L1201 ◽  
Author(s):  
Bing Tian ◽  
Yingxin Zhao ◽  
Hong Sun ◽  
Yueqing Zhang ◽  
Jun Yang ◽  
...  

Chronic epithelial injury triggers a TGF-β-mediated cellular transition from normal epithelium into a mesenchymal-like state that produces subepithelial fibrosis and airway remodeling. Here we examined how TGF-β induces the mesenchymal cell state and determined its mechanism. We observed that TGF-β stimulation activates an inflammatory gene program controlled by the NF-κB/RelA signaling pathway. In the mesenchymal state, NF-κB-dependent immediate-early genes accumulate euchromatin marks and processive RNA polymerase. This program of immediate-early genes is activated by enhanced expression, nuclear translocation, and activating phosphorylation of the NF-κB/RelA transcription factor on Ser276, mediated by a paracrine signal. Phospho-Ser276 RelA binds to the BRD4/CDK9 transcriptional elongation complex, activating the paused RNA Pol II by phosphorylation on Ser2 in its carboxy-terminal domain. RelA-initiated transcriptional elongation is required for expression of the core epithelial-mesenchymal transition transcriptional regulators SNAI1, TWIST1, and ZEB1 and mesenchymal genes. Finally, we observed that pharmacological inhibition of BRD4 can attenuate experimental lung fibrosis induced by repetitive TGF-β challenge in a mouse model. These data provide a detailed mechanism for how activated NF-κB and BRD4 control epithelial-mesenchymal transition initiation and transcriptional elongation in model airway epithelial cells in vitro and in a murine pulmonary fibrosis model in vivo. Our data validate BRD4 as an in vivo target for the treatment of pulmonary fibrosis associated with inflammation-coupled remodeling in chronic lung diseases.

2020 ◽  
Vol 28 (19) ◽  
pp. 115663
Author(s):  
Liqun Wang ◽  
Hongyao Liu ◽  
Qiurong He ◽  
Cailing Gan ◽  
Yali Li ◽  
...  

2019 ◽  
Vol 133 (14) ◽  
pp. 1645-1662 ◽  
Author(s):  
Yan-rong Zhao ◽  
Ji-long Wang ◽  
Cong Xu ◽  
Yi-ming Li ◽  
Bo Sun ◽  
...  

Abstract Heart development protein with EGF-like domains 1 (HEG1) plays critical roles in embryo development and angiogenesis, which are closely related to tumor progression. However, the role of HEG1 in hepatocellular carcinoma (HCC) remains unknown. In the present study, we explored the clinical significance, biological function and regulatory mechanisms of HEG1 in HCC and found that HEG1 is significantly up-regulated in HCC cell lines and primary tumor samples. Additionally, high HEG1 expression is correlated with aggressive clinicopathological features. Patients with high HEG1 expression had shorter overall survival (OS) and disease-free survival (DFS) than those with low HEG1 expression, which indicated that HEG1 is an independent factor for poor prognosis. Lentivirus-mediated HEG1 overexpression significantly promotes HCC cell migration, invasion and epithelial–mesenchymal transition (EMT) in vitro and promotes intrahepatic metastasis, lung metastasis and EMT in vivo. Opposing results are observed when HEG1 is silenced. Mechanistically, HEG1 promotes β-catenin expression and maintains its stability, leading to intracellular β-catenin accumulation, β-catenin nuclear translocation and Wnt signaling activation. Loss- and gain-of-function assays further confirmed that β-catenin is essential for HEG1-mediated promotion of HCC invasion, metastasis and EMT. In conclusion, HEG1 indicates poor prognosis; plays important roles in HCC invasion, metastasis and EMT by activating Wnt/β-catenin signaling; and can serve as a potentially valuable prognostic biomarker and therapeutic target for HCC.


2021 ◽  
Vol 22 (21) ◽  
pp. 11309
Author(s):  
Xinxin Liang ◽  
Ziyan Yan ◽  
Ping Wang ◽  
Yuhao Liu ◽  
Xingkun Ao ◽  
...  

Understanding miRNAs regulatory roles in epithelial-mesenchymal transition (EMT) would help establish new avenues for further uncovering the mechanisms underlying radiation-induced pulmonary fibrosis (RIPF) and identifying preventative and therapeutic targets. Here, we demonstrated that miR-541-5p repression by Myeloid Zinc Finger 1 (MZF1) promotes radiation-induced EMT and RIPF. Irradiation could decrease miR-541-5p expression in vitro and in vivo and inversely correlated to RIPF development. Ectopic miR-541-5p expression suppressed radiation-induced-EMT in vitro and in vivo. Knockdown of Slug, the functional target of miR-541-5p, inhibited EMT induction by irradiation. The upregulation of transcription factor MZF1 upon irradiation inhibited the expression of endogenous miR-541-5p and its primary precursor (pri-miR-541-5p), which regulated the effect of the Slug on the EMT process. Our finding showed that ectopic miR-541-5p expression mitigated RIPF in mice by targeting Slug. Thus, irradiation activates MZF1 to downregulate miR-541-5p in alveolar epithelial cells, promoting EMT and contributing to RIPF by targeting Slug. Our observation provides further understanding of the development of RIPF and determines potential preventative and therapeutic targets.


2020 ◽  
Vol 11 ◽  
Author(s):  
Fei Gao ◽  
Yun Zhang ◽  
Zhizhou Yang ◽  
Mengmeng Wang ◽  
Zhiyi Zhou ◽  
...  

Arctigenin (ATG), a major bioactive substance of Fructus Arctii, counters renal fibrosis; however, whether it protects against paraquat (PQ)-induced lung fibrosis remains unknown. The present study was to determine the effect of ATG on PQ-induced lung fibrosis in a mouse model and the underlying mechanism. Firstly, we found that ATG suppressed PQ-induced pulmonary fibrosis by blocking the epithelial-mesenchymal transition (EMT). ATG reduced the expressions of Vimentin and α-SMA (lung fibrosis markers) induced by PQ and restored the expressions of E-cadherin and Occludin (two epithelial markers) in vivo and in vitro. Besides, the Wnt3a/β-catenin signaling pathway was significantly activated in PQ induced pulmonary fibrosis. Further analysis showed that pretreatment of ATG profoundly abrogated PQ-induced EMT-like phenotypes and behaviors in A549 cells. The Wnt3a/β-catenin signaling pathway was repressed by ATG treatment. The overexpression of Wnt3a could weaken the therapeutic effect of ATG in A549 cells. These findings suggested that ATG could serve as a new therapeutic candidate to inhibit or even reverse EMT-like changes in alveolar type II cells during PQ-induced lung fibrosis, and unraveled that the Wnt3a/β-catenin pathway might be a mechanistic tool for ATG to control pulmonary fibrosis.


2020 ◽  
Vol 11 (11) ◽  
Author(s):  
Ling Peng ◽  
Li Wen ◽  
Qing-Feng Shi ◽  
Feng Gao ◽  
Bin Huang ◽  
...  

AbstractIdiopathic pulmonary fibrosis (IPF) is featured with inflammation and extensive lung remodeling caused by overloaded deposition of extracellular matrix. Scutellarin is the major effective ingredient of breviscapine and its anti-inflammation efficacy has been reported before. Nevertheless, the impact of scutellarin on IPF and the downstream molecular mechanism remain unclear. In this study, scutellarin suppressed BLM-induced inflammation via NF-κB/NLRP3 pathway both in vivo and in vitro. BLM significantly elevated p-p65/p65 ratio, IκBα degradation, and levels of NLRP3, caspase-1, caspase-11, ASC, GSDMDNterm, IL-1β, and IL-18, while scutellarin reversed the above alterations except for that of caspase-11. Scutellarin inhibited BLM-induced epithelial–mesenchymal transition (EMT) process in vivo and in vitro. The expression levels of EMT-related markers, including fibronectin, vimentin, N-cadherin, matrix metalloproteinase 2 (MMP-2) and MMP-9, were increased in BLM group, and suppressed by scutellarin. The expression level of E-cadherin showed the opposite changes. However, overexpression of NLRP3 eliminated the anti-inflammation and anti-EMT functions of scutellarin in vitro. In conclusion, scutellarin suppressed inflammation and EMT in BLM-induced pulmonary fibrosis through NF-κB/NLRP3 signaling.


2019 ◽  
Vol 122 (4) ◽  
pp. 578-589
Author(s):  
Liang Wu ◽  
Zili Zhou ◽  
Shengbo Han ◽  
Jinhuang Chen ◽  
Zhengyi Liu ◽  
...  

Abstract Background We previously demonstrated that the pleomorphic adenoma gene like-2 (PLAGL2) is involved in the pathogenesis of Hirschsprung disease. Enhanced PLAGL2 expression was observed in several malignant tumours. However, the exact function of PLAGL2 and its underlying mechanism in colorectal cancer (CRC) remain largely unknown. Methods Immunohistochemical analysis of PLAGL2 was performed. A series of in vitro and in vivo experiments were conducted to reveal the role of PLAGL2 in the progression of CRC. Results Enhanced PLAGL2 expression was significantly associated with EMT-related proteins in CRC. The data revealed that PLAGL2 promotes CRC cell proliferation, migration, invasion and EMT both in vitro and in vivo. Mechanistically, PLAGL2 promoted the expression of ZEB1. PLAGL2 enhanced the expression and nuclear translocation of β-catenin by decreasing its phosphorylation. The depletion of β-catenin neutralised the regulation of ZEB1 that was caused by enhanced PLAGL2 expression. The small-molecule inhibitor PNU-74654, also impaired the enhancement of ZEB1 that resulted from the modified PLAGL2 expression. The depletion of ZEB1 could block the biological function of PLAGL2 in CRC cells. Conclusions Collectively, our findings suggest that PLAGL2 mediates EMT to promote colorectal cancer metastasis via β-catenin-dependent regulation of ZEB1.


2019 ◽  
Vol 27 (4) ◽  
pp. 1355-1368 ◽  
Author(s):  
Kefei Yuan ◽  
Kunlin Xie ◽  
Tian Lan ◽  
Lin Xu ◽  
Xiangzheng Chen ◽  
...  

Abstract Metastasis is one of the main contributors to the poor prognosis of hepatocellular carcinoma (HCC). However, the underlying mechanism of HCC metastasis remains largely unknown. Here, we showed that TXNDC12, a thioredoxin-like protein, was upregulated in highly metastatic HCC cell lines as well as in portal vein tumor thrombus and lung metastasis tissues of HCC patients. We found that the enforced expression of TXNDC12 promoted metastasis both in vitro and in vivo. Subsequent mechanistic investigations revealed that TXNDC12 promoted metastasis through upregulation of the ZEB1-mediated epithelial–mesenchymal transition (EMT) process. We subsequently showed that TXNDC12 overexpression stimulated the nuclear translocation and activation of β-catenin, a positive transcriptional regulator of ZEB1. Accordingly, we found that TXNDC12 interacted with β-catenin and that the thioredoxin-like domain of TXNDC12 was essential for the interaction between TXNDC12 and β-catenin as well as for TXNDC12-mediated β-catenin activation. Moreover, high levels of TXNDC12 in clinical HCC tissues correlated with elevated nuclear β-catenin levels and predicted worse overall and disease-free survival. In summary, our study demonstrated that TXNDC12 could activate β-catenin via protein–protein interaction and promote ZEB1-mediated EMT and HCC metastasis.


Author(s):  
Yu Wu ◽  
Lili Xu ◽  
Gang Cao ◽  
Lingtian Min ◽  
Tingting Dong

Qingfei Paidu decoction (QFPD) has been repeatedly recommended for the clinical treatment of novel coronavirus disease 2019 (COVID-19) in multiple provinces throughout China. A possible complication of COVID-19 lung involvement is pulmonary fibrosis, which causes chronic breathing difficulties and affects the patient’s quality of life. Therefore, there is an important question regarding whether QFPD can alleviate the process of pulmonary fibrosis and its potential mechanisms. To explore this issue, this study demonstrated the anti-pulmonary fibrosis activity and mode of action of QFPD in vivo and in vitro pulmonary fibrosis models and network pharmacology. The results showed that QFPD effectively ameliorated the bleomycin-induced inflammation and collagen deposition in mice and significantly improved the epithelial-mesenchymal transition in pulmonary fibrosis in mice. In addition, QFPD inhibited bleomycin-induced M2 polarization of macrophages in pulmonary tissues. An in-depth study of the mechanism of QFPD in the treatment of pulmonary fibrosis based on network pharmacology and molecular simulation revealed that SRC was the main target of QFPD and sitosterol (a key compound in QFPD). QFPD and sitosterol regulate the EMT process and M2 polarization of macrophages by inhibiting the activation of SRC, thereby alleviating pulmonary fibrosis in mice. COVID-19 infection might produce severe fibrosis, and antifibrotic therapy with QFPD may be valuable in preventing severe neocoronavirus disease in patients with IPF, which could be a key factor explaining the role of QFPD in the treatment of COVID-19.


2001 ◽  
Vol 281 (4) ◽  
pp. R1274-R1282 ◽  
Author(s):  
Lan Jiang ◽  
Heather Lawsky ◽  
Relicardo M. Coloso ◽  
Mary A. Dudley ◽  
Ronaldo P. Ferraris

C- fos and c- jun are immediate-early genes (IEGs) that are rapidly expressed after a variety of stimuli. Products of these genes subsequently bind to DNA regulatory elements of target genes to modulate their transcription. In rat small intestine, IEG mRNA expression increases dramatically after refeeding following a 48-h fast. We used an in vivo intestinal perfusion model to test the hypothesis that metabolism of absorbed nutrients stimulates the expression of IEGs. Compared with those of unperfused intestines, IEG mRNA levels increased up to 11 times after intestinal perfusion for 0.3–4 h with Ringer solutions containing high (100 mM) fructose (HF), glucose (HG), or mannitol (HM). Abundance of mRNA returned to preperfusion levels after 8 h. Levels of c- fos and c- jun mRNA and proteins were modest and evenly distributed among enterocytes lining the villi of unperfused intestines. HF and HM perfusion markedly enhanced IEG mRNA expression along the entire villus axis. The perfusion-induced increase in IEG expression was inhibited by actinomycin-D. Luminal perfusion induces transient but dramatic increases in c- fos and c- jun expression in villus enterocytes. Induction does not require metabolizable or absorbable nutrients but may involve de novo gene transcription in cells along the villus.


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