ETS1 and RBPJ transcriptionally regulate METTL14 to suppress TGF-ß1-induced epithelial-mesenchymal transition in human bronchial epithelial cells.

Asthma is a chronic respiratory disease characterized by airway inflammation and remodeling. Epithelial-mesenchymal transition (EMT) of bronchial epithelial cells is considered to be a crucial player in asthma. Methyltransferase-like 14 (METTL14), an RNA methyltransferase, is implicated in multiple pathological processes, including EMT, cell proliferation and migration. However, the role of METTL14 in asthma remains uncertain. This research aimed to explore the biological functions of METTL14 in asthma and its underlying upstream mechanisms. METTL14 expression was down-regulated in asthmatic from three GEO datasets (GSE104468, GSE165934, and GSE74986). Consistent with this trend, METTL14 was decreased in the lung tissues of OVA-induced asthmatic mice and transforming growth factor-ß1 (TGF-ß1)-stimulated human bronchial epithelial cells (Beas-2B) in this study. Overexpression of METTL14 caused reduction in mesenchymal markers (FN1, N-cad, Col-1 and α-SMA) in TGF-ß1-treated cells, but caused increase in epithelial markers (E-cad), thus inhibiting EMT. Also, METTL14 suppressed the proliferation and migration ability of TGF-ß1-treated Beas-2B cells. Two transcription factors, ETS1 and RBPJ, could both bind to the promoter region of METTL14 and drive its expression. Elevating METTL14 expression could reversed EMT, cell proliferation and migration promoted by ETS1 or RBPJ deficiency. These results indicate that the ETS1/METTL14 and RBPJ/METTL14 transcription axes exhibit anti-EMT, anti-proliferation and anti-migration functions in TGF-ß1-induced bronchial epithelial cells, implying that METTL14 may be considered an alternative candidate target for the treatment of asthma.

Propylparaben exposure impairs G2/M and metaphase-anaphase transition during mouse oocyte maturation.

Propylparaben (PrPB) is a known endocrine disrupting chemicals that is widely applied as preservative in pharmaceuticals, food and cosmetics. PrPB has been detected in human urine samples and human serum and has been proven to cause functional decline in reproduction. However, the direct effects of PrPB on mammalian oocyte are still unknown. Here, we demonstrationed that exposure to PrPB disturbed mouse oocyte maturation in vitro, causing meiotic resumption arrest and first polar body extrusion failure. Our results indicated that 600 µM PrPB reduced the rate of oocyte germinal vesicle breakdown (GVBD). Further research revealed that PrPB caused mitochondrial dysfunction and oxidative stress, which led to oocyte DNA damage. This damage further disturbed the activity of the maturation promoting factor (MPF) complex Cyclin B1/ Cyclin-dependent kinase 1 (CDK1) and induced G2/M arrest. Subsequent experiments revealed that PrPB exposure can lead to spindle morphology disorder and chromosome misalignment due to unstable microtubules. In addition, PrPB adversely affected the attachment between microtubules and kinetochore, resulting in persistent activation of BUB3 amd BubR1, which are two spindle-assembly checkpoint (SAC) protein. Taken together, our studies indicated that PrPB damaged mouse oocyte maturation via disrupting MPF related G2/M transition and SAC depended metaphase-anaphase transition.

EGR1 transcriptionally regulates SVEP1 to promote proliferation and migration in human coronary artery smooth muscle cells.

A low-frequency variant of sushi, von Willebrand factor type A, EGF, and pentraxin domain-containing protein 1 (SVEP1) is associated with the risk of coronary artery disease, as determined by a genome-wide association study. SVEP1 induces vascular smooth muscle cell proliferation and an inflammatory phenotype to promote atherosclerosis. In the present study, qRT‒PCR demonstrated that the mRNA expression of SVEP1 was significantly increased in atherosclerotic plaques compared to normal tissues. Bioinformatics revealed that EGR1 was a transcription factor for SVEP1. The results of the luciferase reporter assay, siRNA interference or overexpression assay, mutational analysis and ChIP confirmed that EGR1 positively regulated the transcriptional activity of SVEP1 by directly binding to its promoter. EGR1 promoted human coronary artery smooth muscle cell (HCASMC) proliferation and migration via SVEP1 in response to oxidized low-density lipoprotein (ox-LDL) treatment. Moreover, the expression level of EGR1 was increased in atherosclerotic plaques and showed a strong linear correlation with the expression of SVEP1. Our findings indicated that EGR1 binding to the promoter region drive SVEP1 transcription to promote HCASMC proliferation and migration.