ZLJ-6, a novel COX/5-LOX inhibitor, attenuates TNF-α-induced endothelial E-selectin, ICAM-1 and VCAM-1 expression and monocyte-endothelial interactions via a COX/5-LOX-independent mechanism

Integration of single-cell RNA sequencing of endothelial cells and proteomics to unravel the role of ICAM1-PTGS2 communication in apical periodontitis: A laboratory investigation

AIM

Endothelial cells (EDs) play a key role in angiogenesis and are associated with granulomatous lesions in patients with chronic apical periodontitis (CAP). This study aimed to investigate the diversity of EDs using single-cell ribonucleic acid sequencing (scRNA-seq) and to evaluate the regulation of intercellular adhesion molecule 1 (ICAM1) on the ferroptosis-related protein, prostaglandin-endoperoxide synthase 2 (PTGS2), in CAP.

METHODOLOGY

EDs from the uploaded scRNA-seq data of five CAP samples (GSE181688 and GSE197680) were categorized using distinct marker genes. The interactions between vein EDs (veinEndo) and other cell types were analysed using CellPhoneDB. Differentially expressed proteins in the proteomics of human umbilical vein EDs (HUVECs) and THP-1-derived macrophages infected with Porphyromonas gingivalis were compared with the differentially expressed genes (DEGs) of VeinEndo in scRNA-seq of CAP versus healthy control periodontal tissues. The protein-protein interaction of ICAM1-PTGS2 in macrophages and HUVECs was validated by adding recombinant ICAM1, ICAM1 inhibitor and PTGS2 inhibitor using real-time polymerase chain reaction (PCR), western blotting, and immunofluorescence staining.

RESULTS

EDs in patients with CAP were divided into eight subclusters: five vein ED, capillaries, arterials and EC (PLA). There were 29 mutually upregulated DEGs and two mutually downregulated DEGs in vein cells in the scRNA-seq data, as well as differentially expressed proteins in the proteomics of HUVECs. Real-time PCR and immunofluorescence staining showed that ICAM1 and PTGS2 were highly expressed in CAP, infected HUVECs, and macrophages. Recombinant protein ICAM1 may improve PTGS2 expression, reactive oxygen species (ROS), and Fe2+ levels and decrease glutathione peroxidase 4 (GPX4) and SLC7A11 protein levels. ICAM1 inhibitor may inverse the above changes.

CONCLUSIONS

scRNA-seq revealed the diversity of EDs in CAP and identified the possible regulation of ICAM1 by the ferroptosis-related protein, PTGS2, in infected HUVECs and macrophages, thus providing a basis for therapeutic approaches that target the inflammatory microenvironment of CAP.

Angelica sinensis polysaccharides alleviate the oxidative burden on hematopoietic cells by restoring 5-fluorouracil-induced oxidative damage in perivascular mesenchymal progenitor cells

CONTEXT

5-Fluorouracil (5-FU)-injured stromal cells may cause chronic bone marrow suppression; however, the underlying mechanism remains unclear. Angelica sinensis polysaccharide (ASP), the main biologically active ingredient of the Chinese herb, Angelica sinensis (Oliv.) Diels (Apiaceae), may enrich the blood and promote antioxidation.

OBJECTIVE

This study investigated the protective antioxidative effects of ASP on perivascular mesenchymal progenitors (PMPs) and their interactions with hematopoietic cells.

MATERIALS AND METHODS

PMPs were dissociated from C57BL/6 mouse femur and tibia and were subsequently divided into the control, ASP (0.1 g/L), 5-FU (0.025 g/L), and 5-FU + ASP (pre-treatment with 0.1 g/L ASP for 6 h, together with 0.025 g/L 5-FU) then cultured for 48 h. Hematopoietic cells were co-cultured on these feeder layers for 24 h. Cell proliferation, senescence, apoptosis, and oxidative indices were detected, along with stromal osteogenic and adipogenic differentiation potentials. Intercellular and intracellular signaling was analyzed by real-time quantitative reverse transcription polymerase chain reaction and Western blotting.

RESULTS

ASP ameliorated the reactive oxygen species production/scavenge balance in PMPs; improved osteogenic differentiation; increased SCF, CXCL12, VLA-4/VCAM-1, ICAM-1/LFA1, and TPO/MPL, Ang-1/Tie-2 gene expression. Further, the ASP-treated feeder layer alleviated hematopoietic cells senescence (from 21.9 ± 1.47 to 12.1 ± 1.13); decreased P53, P21, p-GSK-3β, β-catenin and cyclin-D1 protein expression, and increased glycogen synthase kinase (GSK)-3β protein expression in co-cultured hematopoietic cells.

DISCUSSION AND CONCLUSIONS

ASP delayed oxidative stress-induced premature senescence of 5-FU-treated feeder co-cultured hematopoietic cells via down-regulation of overactivated Wnt/β-catenin signaling. These findings provide a new strategy for alleviating myelosuppressive stress.

Mechanisms and Future of Non-Small Cell Lung Cancer Metastasis

Lung cancer, renowned for its fast progression and metastatic potency, is rising to become a leading cause of death globally. It has been long observed that lung cancer is particularly ept in spawning distant metastasis at its early stages, and it can readily colonize virtually any human organ. In recent years, cancer research has shed light on why lung cancer is endowed with its exceptional ability to metastasize. In this review, we will take a comprehensive look at the current research on lung cancer metastasis, including molecular pathways, anatomical features and genetic traits that make lung cancer intrinsically metastatic, as we go from lung cancer’s general metastatic potential to the particular metastasis mechanisms in multiple organs. We highly concerned about the advanced discovery and development of lung cancer metastasis, indicating the importance of lung cancer specific gene mutations, heterogeneity or biomarker discovery, and discussing potential opportunities and challenges. We will also introduce some current treatments that targets certain metastatic strategies of non-small cell lung cancer (NSCLC). Advances made in these regards could be critical to our current knowledge base of lung cancer metastasis.

E-Selectin Ligands in the Human Mononuclear Phagocyte System: Implications for Infection, Inflammation, and Immunotherapy

The mononuclear phagocyte system comprises a network of circulating monocytes and dendritic cells (DCs), and “histiocytes” (tissue-resident macrophages and DCs) that are derived in part from blood-borne monocytes and DCs. The capacity of circulating monocytes and DCs to function as the body’s first-line defense against offending pathogens greatly depends on their ability to egress the bloodstream and infiltrate inflammatory sites. Extravasation involves a sequence of coordinated molecular events and is initiated by E-selectin-mediated deceleration of the circulating leukocytes onto microvascular endothelial cells of the target tissue. E-selectin is inducibly expressed by cytokines (tumor necrosis factor-α and IL-1β) on inflamed endothelium, and binds to sialofucosylated glycan determinants displayed on protein and lipid scaffolds of blood cells. Efficient extravasation of circulating monocytes and DCs to inflamed tissues is crucial in facilitating an effective immune response, but also fuels the immunopathology of several inflammatory disorders. Thus, insights into the structural and functional properties of the E-selectin ligands expressed by different monocyte and DC populations is key to understanding the biology of protective immunity and the pathobiology of several acute and chronic inflammatory diseases. This review will address the role of E-selectin in recruitment of human circulating monocytes and DCs to sites of tissue injury/inflammation, the structural biology of the E-selectin ligands expressed by these cells, and the molecular effectors that shape E-selectin ligand cell-specific display. In addition, therapeutic approaches targeting E-selectin receptor/ligand interactions, which can be used to boost host defense or, conversely, to dampen pathological inflammatory conditions, will also be discussed.

COX-2-dependent and independent effects of COX-2 inhibitors and NSAIDs on proatherogenic changes in human monocytes/macrophages

It is the second decade of controversy regarding the cardiovascular effects of cyclo-oxygenase-2 (COX-2) inhibitors. At this time, celecoxib is the only available COX-2-specific inhibitor for treatment of pain and inflammation. Therefore, the present study was designed primarily to determine the impact of celecoxib on cholesterol handling (uptake via scavenger receptors and efflux from the cells) and foam cell formation in human THP-1 macrophages, followed by comparison to rofecoxib and other non-steroidal anti-inflammatory drugs (NSAIDs). THP-1 human macrophages and peripheral blood mononuclear cells were incubated with: celecoxib, rofecoxib, naproxen (at 5, 10, 25 µM) and acetaminophen (0.5 mM, 1 mM)±oxidized low-density lipoprotein (oxLDL, 25 µg/mL). Scavenger receptors: CD36, LOX-1, SR-A1, and CXCL16 and cholesterol efflux proteins: ATP-binding cassette transporter (ABC) A1 and G1, and 27-hydroxylase were detected. The adhesion of monocytes to cultured endothelial cells with/ without COX-2 inhibitors/NSAIDs was also analyzed. The presence of celecoxib and rofecoxib (at high concentrations) significantly decreased expression of 27-hydroxylase and ABCA1, interfering with normal cholesterol outflow from macrophages. Acetaminophen and the non-specific COX inhibitor naproxen had no significant effect on these proteins. Only celecoxib had a profound effect on the class B scavenger receptor CD36 and the class E receptor LOX1. We demonstrate that in contrast to celecoxib, rofecoxib and naproxen increased adhesive properties of monocytes to endothelial cells. This work might contribute to our understanding of multiple mechanisms underlying elevated cardiovascular risk upon the use of COX-2 inhibitors and uncover new possibilities to enhance the safety profile of existing COX-2 inhibitors.

Emodin ameliorates LPS-induced acute lung injury, involving the inactivation of NF-κB in mice

Acute lung injury (ALI) and its severe manifestation of acute respiratory distress syndrome (ARDS) are well-known illnesses. Uncontrolled and self-amplified pulmonary inflammation lies at the center of the pathology of this disease. Emodin, the bio-active coxund of herb Radix rhizoma Rhei, shows potent anti-inflammatory properties through inactivation of nuclear factor-κB (NF-κB). The aim of this study was to evaluate the effect of emodin on lipopolysaccharide (LPS)-induced ALI in mice, and its potential bio-mechanism. In our study, BALB/c mice were stimulated with LPS to induce ALI. After 72 h of LPS stimulation, pulmonary pathological changes, lung injury scores, pulmonary edema, myeloperoxidase (MPO) activity, total cells, neutrophils, macrophages, TNF-α, IL-6 and IL-1β in bronchoalveolar lavage fluid (BALF), and MCP-1 and E-selectin expression were notably attenuated by emodin in mice. Meanwhile, our data also revealed that emodin significantly inhibited the LPS-enhanced the phosphorylation of NF-κB p65 and NF-κB p65 DNA binding activity in lung. Our data indicates that emodin potently inhibits LPS-induced pulmonary inflammation, pulmonary edema and MCP-1 and E-selectin expression, and that these effects were very likely mediated by inactivation of NF-κB in mice. These results suggest a therapeutic potential of emodin as an anti-inflammatory agent for ALI/ARDS treatment.

Relevance of new drug discovery to reduce NF-κB activation in cardiovascular disease

The transcription factor nuclear factor-κB (NF-κB) is a main regulator of the expression of several genes involved in the activation of inflammation, cell proliferation, cell immunity and apoptosis. Excess or inappropriate activation of NF-κB has been observed in human inflammatory diseases, including atherosclerosis. Because of the extensive involvement of NF-κB signaling in human diseases, efforts have been made in developing inhibitors of this pathway. Here we will provide an overview of the biology of NF-κB activation pathways. We will here especially focus on current knowledge of the role of the classical ("canonical") NF-κB activation pathway as a potential therapeutic target for anti-atherosclerotic therapies in clinical applications, and discuss classical and novel therapeutic strategies to reduce its prolonged activation.

Mechanisms for vascular cell adhesion molecule-1 activation of ERK1/2 during leukocyte transendothelial migration

BACKGROUND

During inflammation, adhesion molecules regulate recruitment of leukocytes to inflamed tissues. It is reported that vascular cell adhesion molecule-1 (VCAM-1) activates extracellular regulated kinases 1 and 2 (ERK1/2), but the mechanism for this activation is not known. Pharmacological inhibitors of ERK1/2 partially inhibit leukocyte transendothelial migration in a multi-receptor system but it is not known whether VCAM-1 activation of ERK1/2 is required for leukocyte transendothelial migration (TEM) on VCAM-1.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, we identified a mechanism for VCAM-1 activation of ERK1/2 in human and mouse endothelial cells. VCAM-1 signaling, which occurs through endothelial cell NADPH oxidase, protein kinase Cα (PKCα), and protein tyrosine phosphatase 1B (PTP1B), activates endothelial cell ERK1/2. Inhibition of these signals blocked VCAM-1 activation of ERK1/2, indicating that ERK1/2 is activated downstream of PTP1B during VCAM-1 signaling. Furthermore, VCAM-1-specific leukocyte migration under physiological laminar flow of 2 dynes/cm(2) was blocked by pretreatment of endothelial cells with dominant-negative ERK2 K52R or the MEK/ERK inhibitors, PD98059 and U0126, indicating for the first time that ERK regulates VCAM-1-dependent leukocyte transendothelial migration.

CONCLUSIONS/SIGNIFICANCE

VCAM-1 activation of endothelial cell NADPH oxidase/PKCα/PTP1B induces transient ERK1/2 activation that is necessary for VCAM-1-dependent leukocyte TEM.