The role of tumor necrosis factor-α and interferon-γ in regulating angiomotin-like protein 1 expression in lung microvascular endothelial cells

PRMT1 Ablation in Endothelial Cells Causes Endothelial Dysfunction and Aggravates COPD Attributable to Dysregulated NF-κB Signaling

Endothelial dysfunction and senescence are pivotal in pulmonary diseases, including chronic obstructive pulmonary disease (COPD). Protein arginine methyltransferase 1 (PRMT1) is the major enzyme responsible for asymmetric arginine dimethylation and plays a role in diverse biological processes, including cardiovascular function. Yet, its role in endothelial cells (ECs) remains poorly understood. Here, the role of PRMT1 is investigated in ECs, particularly in the context of COPD pathogenesis. Endothelial-specific PRMT1 knockout mice exhibit pulmonary hemorrhage, inflammation, barrier disruption, and apoptosis, accompanied by hyperactivation of nuclear factor kappa B (NF-κB). Bulk RNA sequencing of whole lungs and single-cell RNA sequencing of pulmonary ECs reveal that endothelial PRMT1 ablation results in a major alteration in inflammation-related gene expression. In a COPD model, PRMT1 deficiency aggravates the COPD phenotypes, including enlarged alveolar spaces, increased cell death, and senescence. PRMT1 inhibition in ECs exacerbates tumor necrosis factor alpha-triggered EC senescence and dysfunction attributable to NF-κB hyperactivation. PRMT1 as a critical regulator of pulmonary EC function, preventing NF-κB-driven endothelial dysfunction and senescence is highlighted here.

Whole-Exome Sequencing of Bronchial Epithelial Cells Reveals a Genetic Print of Airway Remodelling in COPD

The remodelling of the airways is a hallmark of chronic obstructive pulmonary disease, but it is highly heterogeneous and erratically distributed in the airways. To assess the genetic print of remodelling in chronic obstructive pulmonary disease (COPD), we performed a comparative whole-exome sequencing analysis on microdissected bronchial epithelia. Lung resections from four non-COPD and three COPD subjects (ex-smokers and current smokers) were formalin-fixed paraffin-embedded (FFPE). Non-remodelled and remodelled bronchial epithelia were isolated by laser microdissection. Genomic DNA was captured and sequenced. The comparative quantitative analysis identified a list of 109 genes as having variants in remodelled epithelia and 160 genes as having copy number alterations in remodelled epithelia, mainly in COPD patients. The functional analysis highlighted cilia-associated processes. Therefore, bronchial-remodelled epithelia appeared genetically more altered than non-remodelled epithelia. Characterizing the unique molecular print of airway remodelling in respiratory diseases may help uncover additional factors contributing to epithelial dysfunctions, ultimately providing additional targetable proteins to correct epithelial remodelling and improve lung function.

VCAM-1 induces signals that stimulate ZO-1 serine phosphorylation and reduces ZO-1 localization at lung endothelial cell junctions

Endothelial cell VCAM-1 regulates recruitment of lymphocytes, eosinophils, mast cells, or dendritic cells during allergic inflammation. In this report, we demonstrated that, during allergic lung responses, there was reduced zonula occludens (ZO)-1 localization in lung endothelial cell junctions, whereas there was increased lung endothelial cell expression of VCAM-1, N-cadherin, and angiomotin. In vitro, leukocyte binding to VCAM-1 reduced ZO-1 in endothelial cell junctions. Using primary human endothelial cells and mouse endothelial cell lines, Ab crosslinking of VCAM-1 increased serine phosphorylation of ZO-1 and induced dissociation of ZO-1 from endothelial cell junctions, demonstrating that VCAM-1 regulates ZO-1. Moreover, VCAM-1 induction of ZO-1 phosphorylation and loss of ZO-1 localization at cell junctions was blocked by inhibition of VCAM-1 intracellular signals that regulate leukocyte transendothelial migration, including NOX2, PKCα, and PTP1B. Furthermore, exogenous addition of the VCAM-1 signaling intermediate H₂ O₂ (1 μM) stimulated PKCα-dependent and PTP1B-dependent serine phosphorylation of ZO-1 and loss of ZO-1 from junctions. Overexpression of ZO-1 blocked leukocyte transendothelial migration. In summary, leukocyte binding to VCAM-1 induces signals that stimulated ZO-1 serine phosphorylation and reduced ZO-1 localization at endothelial cell junctions during leukocyte transendothelial migration.

Mitigation of tight junction protein dysfunction in lung microvascular endothelial cells with pitavastatin

BACKGROUND

Statin use in individuals with chronic obstructive pulmonary disease (COPD) with coexisting cardiovascular disease is associated with a reduced risk of exacerbations. The mechanisms by which statin plays a role in the pathophysiology of COPD have not been defined. To explore the mechanisms involved, we investigated the effect of statin on endothelial cell function, especially endothelial cell tight junctions.

METHOD

We primarily assessed whether pitavastatin could help mitigate the development of emphysema induced by continuous cigarette smoking (CS) exposure. We also investigated the activation of liver kinase B1 (LKB1)/AMP-activated protein kinase (AMPK) signaling, which plays a role in maintaining endothelial functions, important tight junction proteins, zonula occludens (ZO)-1 and claudin-5 expression, and lung microvascular endothelial cell permeability.

RESULTS

We found that pitavastatin prevented the CS-induced decrease in angiomotin-like protein 1 (AmotL1)-positive vessels via the activation of LKB1/AMPK signaling and IFN-γ-induced hyperpermeability of cultured human lung microvascular endothelial cells by maintaining the levels of AmotL1, ZO-1, and claudin-5 expression at the tight junctions.

CONCLUSION

Our results indicate that the maintenance of lung microvascular endothelial cells by pitavastatin prevents tight junction protein dysfunctions induced by CS. These findings may ultimately lead to new and novel therapeutic targets for patients with COPD.

Vemurafenib resistance selects for highly malignant brain and lung-metastasizing melanoma cells

V600E being the most common mutation in BRAF, leads to constitutive activation of the MAPK signaling pathway. The majority of V600E BRAF positive melanoma patients treated with the BRAF inhibitor vemurafenib showed initial good clinical responses but relapsed due to acquired resistance to the drug. The aim of the present study was to identify possible biomarkers associated with the emergence of drug resistant melanoma cells. To this end we analyzed the differential gene expression of vemurafenib-sensitive and vemurafenib resistant brain and lung metastasizing melanoma cells. The major finding of this study is that the in vitro induction of vemurafenib resistance in melanoma cells is associated with an increased malignancy phenotype of these cells. Resistant cells expressed higher levels of genes coding for cancer stem cell markers (JARID1B, CD271 and Fibronectin) as well as genes involved in drug resistance (ABCG2), cell invasion and promotion of metastasis (MMP-1 and MMP-2). We also showed that drug-resistant melanoma cells adhere better to and transmigrate more efficiently through lung endothelial cells than drug-sensitive cells. The former cells also alter their microenvironment in a different manner from that of drug-sensitive cells. Biomarkers and molecular mechanisms associated with drug resistance may serve as targets for therapy of drug-resistant cancer.

MiR-124 represses vasculogenic mimicry and cell motility by targeting amotL1 in cervical cancer cells

miRNAs have extensive functions in differentiation, metabolism, programmed cell death, and tumor metastasis by post-transcriptional regulation. Vasculogenic mimicry is an important pathway in tumor metastasis. Many factors can regulate vasculogenic mimicry, including miRNAs. In previous studies, miR-124 was found to repress proliferation and metastasis in different types of cancers, but whether it functions in cervical cancer remained unknown. Here, we demonstrate that miR-124 can repress vasculogenic mimicry, migration and invasion in HeLa and C33A cells in vitro. Furthermore, we reveal that the effect of miR-124 on vasculogenic mimicry, migration and invasion results from its interaction with AmotL1. MiR-124 regulates AmotL1 negatively by targeting its 3'untranslated region (3'UTR). We found that miR-124 can repress the EMT process. Together, these results improve our understanding of the function of miR-124 in tumor metastasis and will help to provide new potential target sites for cervical cancer treatment.