β2-Glycoprotein I Inhibits Vascular Endothelial Growth Factor-Induced Angiogenesis by Suppressing the Phosphorylation of Extracellular Signal-Regulated Kinase 1/2, Akt, and Endothelial Nitric Oxide Synthase

In situ hydrogel capturing nitric oxide microbubbles accelerates the healing of diabetic foot

Diabetic foot ulcer (DFU) is a devastating complication in diabetes patients, imposing a high risk of amputation and economic burden on patients. Sustained inflammation and angiogenesis hindrance are thought to be two key drivers of the pathogenesis of such ulcers. Nitric oxide (NO) has been proven to accelerate the healing of acute or chronic wounds by modulating inflammation and angiogenesis. However, the use of gas-based therapeutics is difficult for skin wounds. Herein, therapeutic NO gas was first prepared as stable microbubbles, followed by incorporation into a cold Poloxamer-407 (P₄₀₇) solution. Exposed to the DFU wound, the cold P₄₀₇ solution would rapidly be transformed into a semisolid hydrogel under body temperature and accordingly capture NO microbubbles. The NO microbubble-captured hydrogel (PNO) was expected to accelerate wound healing in diabetic feet. The NO microbubbles had an average diameter of 0.8 ± 0.4 μm, and most of which were captured by the in situ P₄₀₇ hydrogel. Moreover, the NO microbubbles were evenly distributed inside the hydrogel and kept for a longer time. In addition, the gelling temperature of 30% (w/v) P₄₀₇ polymer (21 °C) was adjusted to 31 °C for the PNO gel, which was near the temperature of the skin surface. Rheologic studies showed that the PNO gel had mechanical strength comparable with that of the P₄₀₇ hydrogel. The cold PNO solution was conveniently sprayed or smeared on the wound of DFU and rapidly gelled. In vivo studies showed that PNO remarkably accelerated wound healing in rats with DFU. Moreover, the sustained inflammation at the DFU wound was largely reversed by PNO, as reflected by the decreased levels of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) and the increased levels of anti-inflammatory cytokines (IL-10, IL-22 and IL-13). Meanwhile, angiogenesis was significantly promoted by PNO, resulting in rich blood perfusion at the DFU wounds. The therapeutic mechanism of PNO was highly associated with polarizing macrophages and maintaining the homeostasis of the extracellular matrix. Collectively, PNO gel may be a promising vehicle of therapeutic NO gas for DFU treatment.

The Pathophysiology of The Antiphospholipid Syndrome: A Perspective From The Blood Coagulation System

The antiphospholipid syndrome (APS), a systemic autoimmune disease characterized by a hypercoagulability associated to vascular thrombosis and/or obstetric morbidity, is caused by the presence of antiphospholipid antibodies such as lupus anticoagulant, anti-β-2-glycoprotein 1, and/or anticardiolipin antibodies. In the obstetrical APS, antiphospholipid antibodies induce the production of proinflammatory cytokines and tissue factor by placental tissues and recruited neutrophils. Moreover, antiphospholipid antibodies activate the complement system which, in turn, induces a positive feedback leading to recruitment of neutrophils as well as activation of the placenta. Activation of these cells triggers myometrial contractions and cervical ripening provoking the induction of labor. In thrombotic and obstetrical APS, antiphospholipid antibodies activate endothelial cells, platelets, and neutrophils and they may alter the multimeric pattern and concentration of von Willebrand factor, increase the concentration of thrombospondin 1, reduce the inactivation of factor XI by antithrombin, increase the activation of factor XII, and reduce the activity of tissue plasminogen activator with the subsequent production of plasmin. All these effects result in less permeable clots, denser, thinner, and with more branched fibrin fibers which are more difficult to lysate. As a consequence, thrombosis, the defining clinical criterion of APS, complicates the clinical course of the patient.

In vivo evidence of angiogenesis inhibition by β2-glycoprotein I subfractions in the chorioallantoic membrane of chicken embryos

The vascular network expansion and functioning are important factors affecting normal intra-uterine fetal development. This study addressed the previously reported antiangiogenic potential of beta-2-glycoprotein I (β₂GPI) in vivo in the chick embryo model of angiogenesis. The effects of two naturally occurring β₂GPI forms on the development of the chorioallantoic membrane (CAM) vessels and the chicken embryo were investigated. β₂GPI monomers and dimers were obtained by fractioned purification and characterized using SDS-PAGE, immunoblot, and ELISA. The egg exposure was performed by injection of small volumes of 2.5 µg/mL solutions of the β₂GPI subfractions. Angiogenesis was evaluated through quantitative measurements of vascular architecture parameters in the captured CAM images, using computational analysis of texture contrasts and computer vision techniques. Quantitative information was assigned to the CAM vasculature modifications. In vivo, the β₂GPI dimer completely halted the formation of CAM vessels and led to embryo death after 48 h of exposure. The β₂GPI monomer allowed the embryo to develop up to the 10th day, despite early changes of CAM vessels. The impaired normal vessel growth proceeded as a self-limited effect. The β₂GPI monomer-exposed eggs showed reduced vascularization on the 6th day of incubation, but embryos were viable on the 10th day of incubation, with ingurgitated CAM vessels implying sequelae of the angiogenesis inhibition. Both subfractions impaired CAM vasculature development. The β₂GPI dimer proved to be largely more harmful than the β₂GPI monomer. β₂GPI modification by cleavage or dimerization may play a role in angiogenesis control in vivo.

Long Non-Coding RNA LINC00662 Regulated Proliferation and Migration by Targeting miR-34a-5p/LMAN2L Axis in Glioma

Background

Numerous studies suggest that long non-coding RNAs (lncRNAs) participate in the biological process of diverse malignancies, including glioma. Although many differentially expressed lncRNAs have been identified in glioma, to our best knowledge, the role of LINC00662 and its potential underlying mechanism in glioma progression remains unclear. This study aimed to explore the function and regulatory network of LINC00662 in glioma.

Methods

Expressions of LINC00662, miR-34a-5p and lectin mannose-binding 2-like (LMAN2L) in glioma tissues were analyzed using The Cancer Genome Atlas Program (TCGA) and the Chinese Glioma Genome Atlas (CGGA) databases. Colony formation, Celltiter-Glo and BrdU (5-bromo-2'-deoxyuridine) incorporation assays were used to detect cell proliferation in vitro. Xenograft mouse models were established to determine cell proliferation in vivo. Transwell and wound healing assay was used to detect cell migration. In addition, epithelial-mesenchymal transition (EMT) markers were detected by Western blot. Annexin V and 7-AAD were used to stain apoptotic cells. Interactions between miR-34a-5p and LINC00662 or the 3'-UTR of LMAN2L were predicted and determined by bioinformatics analysis, luciferase reporter assay and RNA immunoprecipitation (RIP) assays.

Results

High LINC00662 level predicted poor overall survival of glioma patients. Functional studies revealed that suppression of LINC00662 remarkably inhibited cell proliferation, clonogenicity and EMT pathway. Mechanistically, LINC00662 sponged miR-34a-5p to regulate LMAN2L expression. Furthermore, miR-34a-5p inhibitor reversed the anti-proliferation and anti-migration effect of LINC00662 knockdown, which could be rescued by downregulation of LMAN2L in glioma cells.

Conclusion

Our study was the first to report that LINC00662 acted as a competing endogenous RNA (ceRNA) to regulate glioma progression by targeting miR-34a-5p/LMAN2L axis, providing a new therapeutic target for glioma.

Structural and functional characterization of β2 -glycoprotein I domain 1 in anti-melanoma cell migration

We previously found that circulating β₂‐glycoprotein I inhibits human endothelial cell migration, proliferation, and angiogenesis by diverse mechanisms. In the present study, we investigated the antitumor activities of β₂‐glycoprotein I using structure‐function analysis and mapped the critical region within the β₂‐glycoprotein I peptide sequence that mediates anticancer effects. We constructed recombinant cDNA and purified different β₂‐glycoprotein I polypeptide domains using a baculovirus expression system. We found that purified β₂‐glycoprotein I, as well as recombinant β₂‐glycoprotein I full‐length (D12345), polypeptide domains I‐IV (D1234), and polypeptide domain I (D1) significantly inhibited melanoma cell migration, proliferation and invasion. Western blot analyses were used to determine the dysregulated expression of proteins essential for intracellular signaling pathways in B16‐F10 treated with β₂‐glycoprotein I and variant recombinant polypeptides. Using a melanoma mouse model, we found that D1 polypeptide showed stronger potency in suppressing tumor growth. Structural analysis showed that fragments A and B within domain I would be the critical regions responsible for antitumor activity. Annexin A2 was identified as the counterpart molecule for β₂‐glycoprotein I by immunofluorescence and coimmunoprecipitation assays. Interaction between specific amino acids of β₂‐glycoprotein I D1 and annexin A2 was later evaluated by the molecular docking approach. Moreover, five amino acid residues were selected from fragments A and B for functional evaluation using site‐directed mutagenesis, and P11A, M42A, and I55P mutations were shown to disrupt the anti‐melanoma cell migration ability of β₂‐glycoprotein I. This is the first study to show the therapeutic potential of β₂‐glycoprotein I D1 in the treatment of melanoma progression.

Angiogenesis in the atherosclerotic plaque

Atherosclerosis is a multifocal alteration of the vascular wall of medium and large arteries characterized by a local accumulation of cholesterol and non-resolving inflammation. Atherothrombotic complications are the leading cause of disability and mortality in western countries. Neovascularization in atherosclerotic lesions plays a major role in plaque growth and instability. The angiogenic process is mediated by classical angiogenic factors and by additional factors specific to atherosclerotic angiogenesis. In addition to its role in plaque progression, neovascularization may take part in plaque destabilization and thromboembolic events. Anti-angiogenic agents are effective to reduce atherosclerosis progression in various animal models. However, clinical trials with anti-angiogenic drugs, mainly anti-VEGF/VEGFR, used in anti-cancer therapy show cardiovascular adverse effects, and require additional investigations.

Aspalatone Prevents VEGF-Induced Lipid Peroxidation, Migration, Tube Formation, and Dysfunction of Human Aortic Endothelial Cells

Although aspalatone (acetylsalicylic acid maltol ester) is recognized as an antithrombotic agent with antioxidative and antiplatelet potential; its efficacy in preventing endothelial dysfunction is not known. In this study, we examined the antiangiogenic, antioxidative, and anti-inflammatory effect of aspalatone in human aortic endothelial cells (HAECs). Specifically, the effect of aspalatone on VEGF-induced HAECs growth, migration, tube formation, and levels of lipid peroxidation-derived malondialdehyde (MDA) was examined. Our results indicate that the treatment of HAECs with aspalatone decreased VEGF-induced cell migration, tube formation, and levels of MDA. Aspalatone also inhibited VEGF-induced decrease in the expression of eNOS and increase in the expression of iNOS, ICAM-1, and VCAM-1. Aspalatone also prevented the VEGF-induced adhesion of monocytes to endothelial cells. Furthermore, aspalatone also prevented VEGF-induced release of inflammatory markers such as Angiopoietin-2, Leptin, EGF, G-CSF, HB-EGF, and HGF in HAECs. Thus, our results suggest that aspalatone could be used to prevent endothelial dysfunction, an important process in the pathophysiology of cardiovascular diseases.