ABSTRACT
BACKGROUND/AIMS: Platelet microvesicles (PMVs) contribute to angiogenesis and vasculogenesis, but the mechanisms underlying these contributions have not been fully elucidated. In the present study, we investigated whether PMVs regulate the angiogenic properties of endothelial cells (ECs) via mechanisms extending beyond the transport of angiogenic regulators from platelets. METHODS: In vitro Matrigel tube formation assay and in vivo Matrigel plug assay were used to evaluate the pro-angiogenic activity of PMVs. The effects of PMVs on the migration of human umbilical vein endothelial cells (HUVECs) were detected by transwell assay and wound-healing assay. Real-time PCR and western blot were conducted to examine mRNA and protein expression of pro-angiogenic factors in HUVECs. Matrix metalloproteinase (MMP) activity was assayed by gelatin zymography. Moreover, the effects of specific MMP inhibitors were tested. RESULTS: PMVs promoted HUVEC capillary-like network formation in a dose-dependent manner. Meanwhile, PMVs dose-dependently facilitated HUVEC migration. Levels of MMP-2 and MMP-9 expression and activity were up-regulated in HUVECs stimulated with PMVs. Inhibition of MMPs decreased their pro-angiogenic and pro-migratory effects on HUVECs. Moreover, we confirmed the pro-angiogenic activity of PMVs in vivo in mice with subcutaneous implantation of Matrigel, and demonstrated that blockade of MMPs attenuated PMV-induced angiogenesis. CONCLUSION: The findings of our study indicate that PMVs promote angiogenesis by up-regulating MMP expression in ECs via mechanism extending beyond the direct delivery of angiogenic factors.
Subject(s)
Human Umbilical Vein Endothelial Cells/enzymology , Matrix Metalloproteinase 2/genetics , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/genetics , Matrix Metalloproteinase 9/metabolism , Neovascularization, Physiologic/physiology , Up-Regulation/physiology , Angiogenesis Inhibitors/pharmacology , Blood Platelets/metabolism , Cell Movement/drug effects , Cell Movement/physiology , Cell Proliferation/drug effects , Cell Proliferation/physiology , Dipeptides/pharmacology , Humans , Matrix Metalloproteinase 2/chemistry , Matrix Metalloproteinase 9/chemistry , Matrix Metalloproteinase Inhibitors/pharmacology , Mitogen-Activated Protein Kinase 1/genetics , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/genetics , Mitogen-Activated Protein Kinase 3/metabolism , Neovascularization, Physiologic/drug effects , Up-Regulation/drug effectsABSTRACT
With application of nano-sized nickel-containing particles (Nano-Ni) expanding, the health concerns about their adverse effects on the pulmonary system are increasing. However, the mechanisms for the pulmonary toxicity of these materials remain unclear. In the present study, we focused on the impacts of NiO nanoparticles (NiONPs) on sirtuin1 (SIRT1), a NAD-dependent deacetylase, and investigated whether SIRT1 was involved in NiONPs-induced apoptosis. Although the NiONPs tended to agglomerate in fluid medium, they still entered into the human bronchial epithelial cells (BEAS-2B) and released Ni(2+) inside the cells. NiONPs at doses of 5, 10, and 20µg/cm(2) inhibited the cell viability. NiONPs' produced cytotoxicity was demonstrated through an apoptotic process, indicated by increased numbers of Annexin V positive cells and caspase-3 activation. The expression of SIRT1 was markedly down-regulated by the NiONPs, accompanied by the hyperacetylation of p53 (tumor protein 53) and overexpression of Bax (Bcl-2-associated X protein). However, overexpression of SIRT1 through resveratrol treatment or transfection clearly attenuated the NiONPs-induced apoptosis and activation of p53 and Bax. Our results suggest that the repression of SIRT1 may underlie the NiONPs-induced apoptosis via p53 hyperacetylation and subsequent Bax activation. Because SIRT1 participates in multiple biologic processes by deacetylation of dozens of substrates, this knowledge of the impact of NiONPs on SIRT1 may lead to an improved understanding of the toxic mechanisms of Nano-Ni and provide a molecular target to antagonize Nano-Ni toxicity.
Subject(s)
Apoptosis/drug effects , Bronchi/metabolism , Epithelial Cells/metabolism , Nanoparticles/toxicity , Nickel/toxicity , Sirtuin 1/antagonists & inhibitors , Bronchi/cytology , Bronchi/drug effects , Caspase 3/metabolism , Cell Line , Cell Survival/drug effects , Down-Regulation/drug effects , Epithelial Cells/drug effects , Humans , Nanoparticles/metabolism , Nickel/metabolism , Sirtuin 1/geneticsABSTRACT
OBJECTIVE: To study the fluoride release ability of two kinds of fluoride-releasing composite resin adhesives made in China. METHODS: Test samples of fluoride-releasing composite resin adhesives I and II were prepared, and fluoride ion concentrations were measured with a No.720 fluoride ion-sensitive electrode. RESULTS: Fluoride ions were released from both of the fluoride-releasing composite resin adhesives. The concentration declined sharply after first 24 hours and maintained at a low level for about 21 days. The initial fluoride ions concentration of adhesive II was higher than adhesive I. CONCLUSION: Both of the fluoride-releasing composite resin adhesives had the ability of releasing fluoride. Adhesive II seemed better.
