New Heterocyclic Combretastatin A-4 Analogs: Synthesis and Biological Activity of Styryl-2(3H)-Benzothiazolones

Here, we describe the synthesis, characterization, and biological activities of a series of 26 new styryl-2(3H)-benzothiazolone analogs of combretastatin-A4 (CA-4). The cytotoxic activities of these compounds were tested in several cell lines (EA.hy926, A549, BEAS-2B, MDA-MB-231, HT-29, MCF-7, and MCF-10A), and the relations between structure and cytotoxicity are discussed. From the series, compound (Z)-3-methyl-6-(3,4,5-trimethoxystyryl)-2(3H)-benzothiazolone (26Z) exhibits the most potent cytotoxic activity (IC50 0.13 ± 0.01 µM) against EA.hy926 cells. 26Z not only inhibits vasculogenesis but also disrupts pre-existing vasculature. 26Z is a microtubule-modulating agent and inhibits a spectrum of angiogenic events in EA.hy926 cells by interfering with endothelial cell invasion, migration, and proliferation. 26Z also shows anti-proliferative activity in CA-4 resistant cells with the following IC50 values: HT-29 (0.008 ± 0.001 µM), MDA-MB-231 (1.35 ± 0.42 µM), and MCF-7 (2.42 ± 0.48 µM). Cell-cycle phase-specific experiments show that 26Z treatment results in G2/M arrest and mitotic spindle multipolarity, suggesting that drug-induced centrosome amplification could promote cell death. Some 26Z-treated adherent cells undergo aberrant cytokinesis, resulting in aneuploidy that perhaps contributes to drug-induced cell death. These data indicate that spindle multipolarity induction by 26Z has an exciting chemotherapeutic potential that merits further investigation.

The Methyltransferase Smyd1 Mediates LPS-Triggered Up-Regulation of IL-6 in Endothelial Cells

The lysine methyltransferase Smyd1 with its characteristic catalytic SET-domain is highly enriched in the embryonic heart and skeletal muscles, participating in cardiomyogenesis, sarcomere assembly and chromatin remodeling. Recently, significant Smyd1 levels were discovered in endothelial cells (ECs) that responded to inflammatory cytokines. Based on these biochemical properties, we hypothesized that Smyd1 is involved in inflammation-triggered signaling in ECs and therefore, investigated its role within the LPS-induced signaling cascade. Human endothelial cells (HUVECs and EA.hy926 cells) responded to LPS stimulation with higher intrinsic Smyd1 expression. By transfection with expression vectors containing gene inserts encoding either intact Smyd1, a catalytically inactive Smyd1-mutant or Smyd1-specific siRNAs, we show that Smyd1 contributes to LPS-triggered expression and secretion of IL-6 in EA.hy926 cells. Further molecular analysis revealed this process to be based on two signaling pathways: Smyd1 increased the activity of NF-κB and promoted the trimethylation of lysine-4 of histone-3 (H3K4me3) within the IL-6 promoter, as shown by ChIP-RT-qPCR combined with IL-6-promoter-driven luciferase reporter gene assays. In summary, our experimental analysis revealed that LPS-binding to ECs leads to the up-regulation of Smyd1 expression to transduce the signal for IL-6 up-regulation via activation of the established NF-κB pathway as well as via epigenetic trimethylation of H3K4.

The Plasma Level of IL-1β As a Biomarker of Angiopathy in Systemic Chronic Active EBV Infection

Background and aim: Systemic chronic active Epstein-Barr virus infection (sCAEBV) is an intractable rare disease revealing persistent systemic inflammation with clonal proliferation of EBV-infected T- or NK-cells. 25% of sCAEBV patients accompany angiopathy such as aneurysm and vasculitis. (Yonese et al. Blood advances. 2020). Because angiopathy degrades patients' quality of life and is one of the main causes of death in sCAEBV, it is crucial to clarify the mechanisms of angiopathy development in sCAEBV. Interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα) are reported to be involved in angiopathy onset. We investigated if IL-1β and TNFα play roles to induce vascular endothelial cell damage in sCAEBV with angiopathy. Methods: sCAEBV patients were diagnosed when meeting all of the following four conditions: 1) inflammation persisting for more than 3 months, 2) increasing EBV-DNA in peripheral blood (PB) or in diseased tissue, 3) EBV infected T- or NK-cells, 4) not applying to other known diseases. We measured the plasma concentration of cytokines by high sensitivity cytokine beads assay (MILLIPLEX ®MAP Kit). We isolated EBV-infected cells and monocytes by magnetic beads (MACS ® Cell Separation). Ea.hy926, a human umbilical vein endothelial cell line, was used as a vascular endothelial cell model. Results: Samples from 17 sCAEBV patients (infected cell types: CD4 in 7; CD8 in 1; and CD56 in 9) and 8 healthy donors were examined. We detected elevated levels of IL-1β in 4 out of 17 sCAEBV patient's plasma. Interestingly, among the 4, 3 had clinically associated angiopathy: 1 aneurysm, 1 vasculitis, and 1 intracranial vascular lesions with multiple cerebral infarctions. The EBV-infected cells of these 3 patients were CD4-positive cells. The TNFα concentration of patients' plasma was higher than that of healthy donors, but there was no correlation with angiopathy. The mRNA of IL-1β in the EBV-infected cells of patients with high plasma IL-1β was not enhanced compared to that of patients with undetectable plasma IL-1β. In one patient with high plasma IL-1β, the level of IL-1β mRNA of the monocytes was 17.2 times higher than the level of the same patient's EBV-infected cells. IL-1β inhibited the proliferation of Ea.hy926 cells. IL-1β upregulated the mRNA expression of Tissue factor (TF) as well as Plasminogen activator inhibitor-1 (PAI-1) and suppressed the mRNA of Thrombomodulin (TM) in Ea.hy926 cells. Discussion: IL-1β originally exists in immunocompetent cells such as CD4-positive cells in the form of precursor protein (pro-IL-1β). In the occurrence of inflammation, pro-IL-1β is cleaved by caspase-1 activated by the inflammasome, and the production and the secretion of IL-1β is induced without mRNA elevation. The infected cells of sCAEBV patients with high level plasma IL-1β and vascular lesion were all CD4-positive. Consequently, we suspect that EBV-infected, CD4-positive cells are responsible for the production of IL-1β. Likewise, we detected high expression of IL-1β in monocytes derived from a patient with high plasma IL-1β. Based on these facts, we set two hypotheses on the production of IL-1β in sCAEBV. One is the production in EBV-infected cells by the cleavage of pro-IL-1β. The other is the production through transcription and translation in monocytes. IL-1β suppressed the proliferation of Ea.hy926 cells. In the same cells, IL-1β also induced TF and PAI-1 expression and suppressed TM expression. These results suggest that IL-1β may induce vascular damage and blood coagulation to cause angiopathy. Conclusion: In sCAEBV, IL-1β may be a biomarker of angiopathy. IL-1β may be a therapeutic target to treat sCAEBV accompanying vascular lesions. Disclosures Arai: Abbvie GK: Honoraria; BMS: Honoraria; Chugai Pharmaceutical Co Ltd: Honoraria, Research Funding; Eisai Co Ltd: Research Funding; Abbott Japan LLC: Honoraria; Kyowa Kirin Co ltd: Honoraria, Research Funding; Ono Pharmaceutical Co ltd: Honoraria, Research Funding; Nippon Shinyaku Co Ltd: Honoraria, Research Funding; Otsuka Pharmaceutical Co ltd: Research Funding; Novartis Pharma KK: Honoraria; Takeda Pharmaceuticals Co Ltd: Honoraria, Research Funding; Shionogi & Co ltd: Research Funding; Asahi Kasei Pharma Corporation: Research Funding; Sanofi KK: Honoraria; Pfizer Japan Inc: Honoraria; Astellas Pharma Inc: Honoraria.

Altered Moesin and Actin Cytoskeleton Protein Rearrangements Affect Transendothelial Permeability in Human Endothelial Cells upon Dengue Virus Infection and TNF-α Treatment

It has been hypothesized that the host, viral factors, and secreted cytokines (especially TNF-α) play roles in the pathogenesis of secondary dengue infections. Mass spectrometry-based proteomic screening of cytoskeleton fractions isolated from human endothelial (EA.hy926) cells upon dengue virus (DENV) infection and TNF-α treatment identified 450 differentially altered proteins. Among them, decreased levels of moesin, actin stress fiber rearrangements, and dot-like formations of vinculin were observed with western blot analyses and/or immunofluorescence staining (IFA). In vitro vascular permeability assays using EA.hy926 cells, seeded on collagen-coated transwell inserts, showed low levels of transendothelial electrical resistance in treated cells. The synergistic effects of DENV infection and TNF-α treatment caused cellular permeability changes in EA.hy926 cells, which coincided with decreasing moesin levels and the production of abnormal organizations of actin stress fibers and vinculin. Functional studies demonstrated moesin overexpression restored transendothelial permeability in DENV/TNF-α-treated EA.hy926 cells. The present study improves the understanding of the disruption mechanisms of cytoskeleton proteins in enhancing vascular permeability during DENV infection and TNF-α treatment. The study also suggests that these disruption mechanisms are major factors contributing to vascular leakage in severe dengue patients.

Dendrobium catenatum Lindl. Water Extracts Attenuate Atherosclerosis

Objectives. Dendrobium catenatum Lindl. (DH) is a Chinese herbal medicine, which is often used to make tea to improve immunity in China. Rumor has it that DH has a protective effect against cardiovascular disease. However, it is not clear how DH can prevent cardiovascular disease, such as atherosclerosis (AS). Therefore, the purpose of this study is to study whether DH can prevent AS and the underlying mechanisms. Methods. Zebrafish larvae were fed with high-cholesterol diet (HCD) to establish a zebrafish AS model. Then, we used DH water extracts (DHWE) to pretreat AS zebrafish. The plaque formation was detected by HE, EVG, and oil red O staining. Neutrophil and macrophage counts were calculated to evaluate the inflammation level. Reactive oxygen species (ROS) activity, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity in zebrafish were measured to reflect oxidative stress. The cholesterol accumulation and the levels of lipid, triglyceride (TG), and total cholesterol (TC) were measured to reflect lipid metabolism disorder. Then, parallel flow chamber was utilized to establish a low shear stress- (LSS-) induced endothelial cell (EC) dysfunction model. EA.hy926 cells were exposed to LSS (3 dyn/cm2) for 30 min and treated with DHWE. The levels of ROS, SOD, MDA, glutathione (GSH), and glutathiol (GSSG) in EA.hy926 cells were analysed to determine oxidative stress. The release of nitric oxide (NO), endothelin-1 (ET-1), and epoprostenol (PGI2) in EA.hy926 cells was measured to reflect EC dysfunction. The mRNA expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in EA.hy926 cells was detected to reflect EC dysfunction inflammation. Results. The results showed that DHWE significantly reduced cholesterol accumulation and macrophage infiltration in early AS. Finally, DHWE significantly alleviate the lipid metabolism disorder, oxidative stress, and inflammation to reduce the plaque formation of AS zebrafish larval model. Meanwhile, we also found that DHWE significantly improved LSS-induced EC dysfunction and oxidative stress in vitro. Conclusion. Our results indicate that DHWE could be used as a prevention method to prevent AS.

Oridonin Attenuates Low Shear Stress-Induced Endothelial Cell Dysfunction and Oxidative Stress by Activating The Nuclear Factor Erythroid 2-Related Factor 2 Pathway

Background Atherosclerosis (AS) is the primary cause of cardiovascular disease and the incidence is extremely common; however, there are currently few drugs that can effectively treat AS. Although oridonin has been widely used to treat inflammation and cancer for numerous years, to the best of our knowledge, its protective effect against AS has not been reported. Therefore, the present study aimed to investigate whether oridonin attenuated AS. Methods By using text mining, chemometric and chemogenomic methods, oridonin was predicted to be a beneficial agent for the treatment of AS. A parallel flow chamber was used to establish a low shear stress (LSS)-induced endothelial cell (EC) dysfunction model. Briefly, ECs were exposed to 3 dyn/cm2 LSS for 30 min and subsequently treated with oridonin or transfected with a small interfering RNA (siRNA) targeting nuclear factor erythroid 2-related factor 2 (NRF2). Reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH) and glutathione disulfide (GSSG) in EA.hy926 cells were analyzed to determine the level of oxidative stress. The nitric oxide (NO) levels and mRNA expression levels of endothelial NO synthase (eNOS), endothelin-1 (ET-1) and prostaglandin synthase (PGIS) in EA.hy926 cells were analyzed to determine EC dysfunction. Furthermore, the mRNA expression levels of NRF2 were analyzed using reverse transcription-quantitative PCR. In addition, zebrafish were fed with a high-cholesterol diet to establish a zebrafish AS model, which was used to observe lipid accumulation and inflammation under a fluorescence microscope. Results We found LSS led to oxidative stress and EC dysfunction; this was primarily indicated through the significantly decreased SOD and GSH content, the significantly increased MDA, GSSG and ROS content, the upregulated mRNA expression levels of ET-1, and the downregulated NO levels and mRNA expression levels of eNOS and PGIS in ECs. Notably, oridonin could improve LSS-induced oxidative stress and EC dysfunction,and the effects of oridonin were reversed by the transfection with NRF2 siRNA. Oridonin also attenuated lipid accumulation and neutrophil recruitment at the LSS regions in the zebrafish AS model. Conclusions In conclusion, the results of the present study suggested that oridonin may ameliorate LSS-induced EC dysfunction and oxidative stress by activating NRF2, thereby attenuating AS.

Rapid Internalization and Nuclear Translocation of CCL5 and CXCL4 in Endothelial Cells

The chemokines CCL5 and CXCL4 are deposited by platelets onto endothelial cells, inducing monocyte arrest. Here, the fate of CCL5 and CXCL4 after endothelial deposition was investigated. Human umbilical vein endothelial cells (HUVECs) and EA.hy926 cells were incubated with CCL5 or CXCL4 for up to 120 min, and chemokine uptake was analyzed by microscopy and by ELISA. Intracellular calcium signaling was visualized upon chemokine treatment, and monocyte arrest was evaluated under laminar flow. Whereas CXCL4 remained partly on the cell surface, all of the CCL5 was internalized into endothelial cells. Endocytosis of CCL5 and CXCL4 was shown as a rapid and active process that primarily depended on dynamin, clathrin, and G protein-coupled receptors (GPCRs), but not on surface proteoglycans. Intracellular calcium signals were increased after chemokine treatment. Confocal microscopy and ELISA measurements in cell organelle fractions indicated that both chemokines accumulated in the nucleus. Internalization did not affect leukocyte arrest, as pretreatment of chemokines and subsequent washing did not alter monocyte adhesion to endothelial cells. Endothelial cells rapidly and actively internalize CCL5 and CXCL4 by clathrin and dynamin-dependent endocytosis, where the chemokines appear to be directed to the nucleus. These findings expand our knowledge of how chemokines attract leukocytes to sites of inflammation.

Cytoprotection against Oxidative Stress by Methylnissolin-3-O-β-D-glucopyranoside from Astragalus membranaceus Mainly via the Activation of the Nrf2/HO-1 Pathway

Astragalus membranaceus is a famous herb found among medicinal and food plants in East and Southeastern Asia. The Nrf2-ARE assay-guided separation of an extract from Jing liqueur led to the identification of a nontoxic Nrf2 activator, methylnissolin-3-O-β-D-glucopyranoside (MNG, a component of A. membranaceus). Nrf2 activation by MNG has not been reported before. Using Western Blot, RT-qPCR and imaging, we investigated the cytoprotective effect of MNG against hydrogen peroxide-induced oxidative stress. MNG induced the expression of Nrf2, HO-1 and NQO1, accelerated the translocation of Nrf2 into nuclei, and enhanced the phosphorylation of AKT. The MNG-induced expression of Nrf2, HO-1, and NQO1 were abolished by Nrf2 siRNA, while the MNG-induced expression of Nrf2 and HO-1 was abated and the AKT phosphorylation was blocked by LY294002 (a PI3K inhibitor). MNG reduced intracellular ROS generation. However, the protection of MNG against the H2O2 insult was reversed by Nrf2 siRNA with decreased cell viability. The enhancement of Nrf2 and HO-1 by MNG upon H2O2 injury was reduced by LY294002. These data showed that MNG protected EA.hy926 cells against oxidative damage through the Nrf2/HO-1 and at least partially the PI3K/Akt pathways.

Aldosterone Negatively Regulates Nrf2 Activity: An Additional Mechanism Contributing to Oxidative Stress and Vascular Dysfunction by Aldosterone

High levels of aldosterone (Aldo) trigger oxidative stress and vascular dysfunction independent of effects on blood pressure. We sought to determine whether Aldo disrupts Nrf2 signaling, the main transcriptional factor involved in antioxidant responses that aggravate cell injury. Thoracic aorta from male C57Bl/6J mice and cultured human endothelial cells (EA.hy926) were stimulated with Aldo (100 nM) in the presence of tiron [reactive oxygen species (ROS) scavenger, eplerenone [mineralocorticoid receptor (MR) antagonist], and L-sulforaphane (SFN; Nrf2 activator). Thoracic aortas were also isolated from mice infused with Aldo (600 μg/kg per day) for 14 days. Aldo decreased endothelium-dependent vasorelaxation and increased ROS generation, effects prevented by tiron and MR blockade. Pharmacological activation of Nrf2 with SFN abrogated Aldo-induced vascular dysfunction and ROS generation. In EA.hy926 cells, Aldo increased ROS generation, which was prevented by eplerenone, tiron, and SFN. At short times, Aldo-induced ROS generation was linked to increased Nrf2 activation. However, after three hours, Aldo decreased the nuclear accumulation of Nrf2. Increased Keap1 protein expression, but not activation of p38 MAPK, was linked to Aldo-induced reduced Nrf2 activity. Arteries from Aldo-infused mice also exhibited decreased nuclear Nrf2 and increased Keap1 expression. Our findings suggest that Aldo reduces vascular Nrf2 transcriptional activity by Keap1-dependent mechanisms, contributing to mineralocorticoid-induced vascular dysfunction.