Angiostatin K1-3 induces E-selectin via AP1 and Ets1: a mediator for anti-angiogenic action of K1-3

E-selectin in vascular pathophysiology

Selectins are a group of Ca2+-dependent, transmembrane type I glycoproteins which attract cell adhesion and migration. E-selectin is exclusively expressed in endothelial cells, and its expression is strongly enhanced upon activation by pro-inflammatory cytokines. The interaction of E-selectin with its ligands on circulating leukocytes captures and slows them down, further facilitating integrin activation, firm adhesion to endothelial cells and transmigration to tissues. Oxidative stress induces endothelial cell injury, leading to aberrant expression of E-selectin. In addition, the elevated level of E-selectin is positively related to high risk of inflammation. Dysregulation of E-selectin has been found in several pathological conditions including acute kidney injury (AKI), pulmonary diseases, hepatic pathology, Venous thromboembolism (VTE). Deletion of the E-selectin gene in mice somewhat ameliorates these complications. In this review, we describe the mechanisms regulating E-selectin expression, the interaction of E-selectin with its ligands, the E-selectin physiological and pathophysiological roles, and the therapeutical potential of targeting E-selectin.

The effect of exercise on blood concentrations of angiogenesis markers in older adults: A systematic review and meta-analysis

Impaired angiogenesis is associated with cognitive decline in older adults. While exercise has been broadly associated with increased angiogenesis, the relevant mechanisms in older adults are not clear. Here, we present a systematic review and meta-analysis on the relationship between exercise and specific blood angiogenesis markers in older adults to better understand the relevant mechanisms. MEDLINE, Embase, and Cochrane CENTRAL were searched for original reports of angiogenesis markers' concentrations in blood before and after exercise in older adults (≥50 years). Heterogeneity was investigated using sub-group analyses and meta-regressions. Of the 44 articles included in the review, 38 were included in the meta-analyses for five markers: vascular endothelial growth factor (VEGF), e-selectin (CD62E), endostatin, fibroblast growth factor 2, and matrix metallopeptidase-9. VEGF levels were higher (SMD[95%CI]= 0.18[0.03, 0.34], and CD62E levels were lower (SMD[95%CI]= -0.72[-1.42, -0.03], p = 0.04) after exercise. No other markers were altered. Although more studies are needed, changes in angiogenesis markers may help explain the beneficial effects of exercise on angiogenesis in older adults.

Oxidative Stress Induces E-Selectin Expression through Repression of Endothelial Transcription Factor ERG

Oxidative stress induces a prothrombotic state through enhancement of adhesion properties of the endothelium. E-selectin, an endothelial cell adhesion molecule, becomes a therapeutic target for venous thrombosis, whereas the regulatory mechanisms of its expression have not been fully understood. In the present study, we report that H2O2 treatment increases expression of E-selectin but decreases expression of the endothelial transcription factor ETS-related gene (ERG) in HUVECs in a dose- and time-dependent manner. In BALB/c mice treated with hypochlorous acid, E-selectin expression is increased and ERG expression is decreased in endothelial cells of the brain and lung. RNA interference of ERG upregulates E-selectin expression, whereas transfection of ERG-expressing plasmid downregulates E-selectin expression in HUVECs. Knockdown or overexpression of ERG comprises H2O2-induced E-selectin expression in HUVECs. Deletion of the Erg gene in mice results in embryonic lethality at embryonic days 10.5-12.5, and E-selectin expression is increased in the Erg-/- embryos. No chromatin loop was found on the E-selectin gene or its promoter region by capture high-throughput chromosome conformation capture. Chromatin immunoprecipitation and luciferase reporter assay determined that the -127 ERG binding motif mediates ERG-repressed E-selectin promoter activity. In addition, ERG decreases H2O2-induced monocyte adhesion. Together, ERG represses the E-selectin gene transcription and inhibits oxidative stress-induced endothelial cell adhesion.

The effect of exercise on blood concentrations of angiogenesis markers in older adults: a systematic review and meta-analysis

Background

Physical exercise has positive impacts on health and can improve angiogenesis, which is impaired during aging, but the underlying mechanisms of benefit are unclear. This meta-analysis and systematic review investigated the effects of exercise on several peripheral angiogenesis markers in older adults to better understand the relationship between exercise and angiogenesis.

Methods

MEDLINE, Embase, and Cochrane CENTRAL were searched for original, peer-reviewed reports of peripheral concentrations of angiogenesis markers before and after exercise interventions in older adults (> 50 years). The risk of bias was assessed with standardized criteria. Standardized mean differences (SMD) with 95% confidence intervals (CIs) were calculated from random-effects models. Publication bias was assessed with Egger's test, funnel plots, and trim-and-fill. A priori subgroup analyses and meta-regressions were performed to investigate heterogeneity where possible.

Results

Of the 44 articles included in the review, 38 were included in meta-analyses for five proteins. Vascular endothelial growth factor (VEGF) was found to be higher after exercise (SMD[95%CI] = 0.18[0.03, 0.34], p = 0.02), and e-selectin (CD62E) was found to be lower after exercise (SMD[95%CI]= -0.72[-1.42, -0.03], p = 0.04). Endostatin (SMD[95%CI] = 0.28[-0.56, 1.11], p = 0.5), fibroblast growth factor 2 (SMD[95%CI] = 0.03[-0.18, 0.23], p = 0.8), and matrix metallopeptidase-9 (SMD[95%CI] = -0.26[-0.97, 0.45], p = 0.5) levels did not change after exercise.

Conclusions

Of the five angiogenesis blood markers evaluated in this meta-analysis, only VEGF and CD62E changed with exercise. Although more studies are needed, changes in angiogenesis markers may explain the beneficial effects of exercise on angiogenesis and health in older adults.

Angiostatin inhibits acute lung injury in a mouse model

Acute lung injury is marked by profound influx of activated neutrophils, which have delayed apoptosis, along with fluid accumulation that impairs lung function and causes high mortality. Inflammatory and antimicrobial molecules, such as reactive oxygen species from activated neutrophils with prolonged lifespan, cause tissue damage and contribute to lung dysfunction. Angiostatin, an endogenous antiangiogenic molecule, is expressed in the lavage fluid of patients with acute respiratory distress syndrome and modifies neutrophil infiltration in a mouse model of peritonitis. Our aim was to investigate the therapeutic role of angiostatin in acute lung injury. We analyzed bronchoalveolar lavage and lung tissues from C57BL/6 mouse model of Escherichia coli LPS-induced acute lung injury to assess the effects of angiostatin treatment. Subcutaneous angiostatin administered at 5 h after LPS treatment reduces histological signs of inflammation, protein accumulation, lung Gr1+ neutrophils, myeloperoxidase activity, and expression of phosphorylated p38 MAPK in lung tissues and peripheral blood neutrophils, while increasing the number of apoptotic cells in the lungs without affecting the levels of macrophage inflammatory protein-1 α, IL-1β, keratinocyte chemoattractant, and monocyte chemoattractant protein-1 in lavage and lung homogenates at 9 and 24 h after LPS treatment. In contrast, angiostatin administered intravenously 5 h after LPS treatment did not reduce histological sign of inflammation, BAL cell recruitment, and protein concentration at 9 h of LPS treatment. We conclude that angiostatin administered subcutaneously after LPS challenge inhibits acute lung inflammation up to 24 h after LPS treatment.

The mechanism underlying the effects of the cell surface ATP synthase on the regulation of intracellular acidification during acidosis

The F1F0 ATP synthase has recently become the focus of anti-cancer research. It was once thought that ATP synthases were located strictly on the inner mitochondrial membrane; however, in 1994, it was found that some ATP synthases localized to the cell surface. The cell surface ATP synthases are involved in angiogenesis, lipoprotein metabolism, innate immunity, hypertension, the regulation of food intake, and other processes. Inhibitors of this synthase have been reported to be cytotoxic and to induce intracellular acidification. However, the mechanisms by which these effects are mediated and the molecular pathways that are involved remain unclear. In this study, we aimed to determine whether the inhibition of cell proliferation and the induction of cell apoptosis that are induced by inhibitors of the cell surface ATP synthase are associated with intracellular acidification and to investigate the mechanism that underlines the effects of this inhibition, particularly in an acidic tumor environment. We demonstrated that intracellular acidification contributes to the cell proliferation inhibition that is mediated by cell surface ATP synthase inhibitors, but not to the induction of apoptosis. Intracellular acidification is only one of the mechanisms of ecto-ATP synthase-targeted antitumor drugs. We propose that intracellular acidification in combination with the inhibition of cell surface ATP generation induce cell apoptosis after cell surface ATP synthase blocked by its inhibitors. A better understanding of the mechanisms activated by ecto-ATP synthase-targeted cancer therapies may facilitate the development of potent anti-tumor therapies, which target this enzyme and do not exhibit clinical limitations.