Tropoelastin enhances nitric oxide production by endothelial cells

The role of extracellular matrix in tumour angiogenesis: the throne has NOx servants

The extracellular matrix (ECM) dynamics in tumour tissue are deregulated compared to the ECM in healthy tissue along with disorganized architecture and irregular behaviour of the residing cells. Nitric oxide (NO) as a pleiotropic molecule exerts different effects on the components of the ECM driving or inhibiting augmented angiogenesis and tumour progression and tumour cell proliferation and metastasis. These effects rely on the concentration of NO within the tumour tissue, the nature of the surrounding microenvironment and the sensitivity of resident cells to NO. In this review article, we summarize the recent findings on the correlation between the levels of NO and the ECM components towards the modulation of tumour angiogenesis in different types of cancers. These are discussed principally in the context of how NO modulates the expression of ECM proteins resulting in either the promotion or inhibition of tumour growth via tumour angiogenesis. Furthermore, the regulatory effects of individual ECM components on the expression of the NO synthase enzymes and NO production were reviewed. These findings support the current efforts for developing effective therapeutics for cancers.

Ginsenoside Rg1-Notoginsenoside R1-Protocatechuic Aldehyde Reduces Atherosclerosis and Attenuates Low-Shear Stress-Induced Vascular Endothelial Cell Dysfunction

Background: The Fufang Danshen formula is a clinically important anti-atherosclerotic preparation in traditional Chinese medicine. However, its anti-atherosclerotic effect is not well recognized, and the mechanisms of its combined active ingredients, namely Ginsenoside Rg1-Notoginsenoside R1-Protocatechuic aldehyde (RRP), remain unclear. The purpose of this study was to investigate the anti-atherosclerotic effects and potential mechanism of RRP in ApoE-/- mice and in low-shear stress-injured vascular endothelial cells. Methods: ApoE-/- mice were randomly divided into three groups: model group, rosuvastatin group, and RRP group, with C57BL/6J mice as the control group. Oil-red O, hematoxylin and eosin, Masson, and Movat staining were utilized for the observation of aortic plaque. Changes in the blood lipid indexes were observed with an automatic biochemistry analyzer. ET-1, eNOS, TXA2, and PGI2 levels were analyzed by enzyme-linked immunosorbent assay. In vitro, a fluid shear stress system was used to induce cell injury. Piezo1 expression in HUVECs was silenced using siRNA. Changes in morphology, proliferation, migration, and tube formation activity of cells were observed after RRP treatment. Quantitative Real-Time PCR and western blot analysis were employed to monitor mRNA and protein expression. Results: RRP treatment reduced the atherosclerotic area and lipid levels and improved endothelial function in ApoE-/- mice. RRP significantly repaired cell morphology, reduced excessive cell proliferation, and ameliorated migration and tube formation activity. In addition, RRP affected the FAK-PI3K/Akt signaling pathway. Importantly, Piezo1 silencing abolished the protective effects of RRP. Conclusion: RRP has anti-atherosclerotic effects and antagonizes endothelial cell damage via modulating the FAK-PI3K/Akt signaling pathway. Piezo1 is a possible target of RRP in the treatment of atherosclerosis. Thus, RRP has promising therapeutic potential and broad application prospect for atherosclerosis.

TRAIL signals, extracellular matrix and vessel remodelling

The extracellular matrix (ECM) is an essential part of the vasculature, not only providing structural support to the blood vessel wall, but also in its ability to interact with cells to regulate cell phenotype and function including proliferation, migration, differentiation and death – processes important in vascular remodelling. Increasing evidence implicates TNF-related apoptosis-inducing ligand (TRAIL) signalling in the modulation of vascular cell function and remodelling under normal and pathological conditions such as in atherosclerosis. TRAIL can also stimulate synthesis of multiple ECM components within blood vessels. This review explores the relationship between TRAIL signals, the ECM, and its implications in vessel remodelling in cardiovascular disease.

The VGVAPG Peptide Regulates the Production of Nitric Oxide Synthases and Reactive Oxygen Species in Mouse Astrocyte Cells In Vitro

The products of elastin degradation, namely elastin-derived peptides (EDPs), are detectable in the cerebrospinal fluid of healthy individuals and in patients after ischemic stroke, and their number increases with age. Depending on their concentrations, both nitric oxide (NO) and reactive oxygen species (ROS) take part either in myocardial ischemia reperfusion injury or in neurovascular protection after ischemic stroke. The aim of our study was to determine the impact of VGVAPG peptide on ROS and NO production and expression of endothelial nitric oxide synthase (eNos), inducible nitric oxide synthase (iNos) and neuronal nitric oxide synthase (nNos) in mouse cortical astrocytes in vitro. Primary astrocytes were maintained in DMEM/F12 without phenol red supplemented with 10% fetal bovine serum. The cells were exposed to rising VGVAPG peptide concentrations, and ROS and NO production was measured. After 6 h (for mRNA) and 24 (for the protein) of exposure to 10 nM and 1 µM of the peptide, expression of nNos, iNos and eNos was measured. Moreover, the Glb1 siRNA gene knockdown method and Pioglitazone, a peroxisome proliferator-activated receptor gamma (Pparγ) agonist, were applied. Our study shows that the VGVAPG peptide decreased eNos, iNos and nNos mRNA and protein expression in mouse astrocytes in vitro. The VGVAPG peptide also decreased NO production while increasing ROS production in the cells. Furthermore, silencing of the Glb1 gene reversed all effects caused by the VGVAPG peptide. However, due to the lack of sufficient data explaining the molecular mechanism of action of the VGVAPG peptide in the nervous system, more studies in this area are necessary.

Tropoelastin Implants That Accelerate Wound Repair

A novel, pure, synthetic material is presented that promotes the repair of full-thickness skin wounds. The active component is tropoelastin and leverages its ability to promote new blood vessel formation and its cell recruiting properties to accelerate wound repair. Key to the technology is the use of a novel heat-based, stabilized form of human tropoelastin which allows for tunable resorption. This implantable material contributes a tailored insert that can be shaped to the wound bed, where it hydrates to form a conformable protein hydrogel. Significant benefits in the extent of wound healing, dermal repair, and regeneration of mature epithelium in healthy pigs are demonstrated. The implant is compatible with initial co-treatment with full- and split-thickness skin grafts. The implant's superiority to sterile bandaging, commercial hydrogel and dermal regeneration template products is shown. On this basis, a new concept for a prefabricated tissue repair material for point-of-care treatment of open wounds is provided.

Perspectives on the Molecular and Biological Implications of Tropoelastin in Human Tissue Elasticity

The elasticity of a range of vertebrate and particularly human tissues depends on the dynamic and persistent protein elastin. This elasticity is diverse, and comprises skin, blood vessels, and lung, and is essential for tissue viability. Elastin is predominantly made by assembling tropoelastin, which is an asymmetric 20-nm-long protein molecule. This overview considers tropoelastin’s molecular features and biological interactions in the context of its value in tissue repair.