ABSTRACT
Atherosclerosis is a chronic inflammatory disease, whose progression and stability are modulated, among other factors, by an innate and adaptive immune response. Prodiginines are bacterial secondary metabolites with antiproliferative and immunomodulatory activities; however, their effect on the progression or vulnerability of atheromatous plaque has not been evaluated. This study assessed the therapeutic potential of prodigiosin and undecylprodigiosin on inflammatory marker expression and atherosclerosis. An in vitro and in vivo study was carried out. Migration, low-density lipoprotein (LDL) uptake and angiogenesis assays were performed on cell types involved in the pathophysiology of atherosclerosis. In addition, male LDL receptor null (Ldlr-/-) C57BL/6J mice were treated with prodigiosin or undecylprodigiosin for 28 days. Morphometric analysis of atherosclerotic plaques, gene expression of atherogenic factors in the aortic sinus and serum cytokine quantification were performed. The treatments applied had slight effects on the in vitro tests performed, highlighting the inhibitory effect on the migration of SMCs (smooth muscle cells). On the other hand, although no significant difference in atherosclerotic plaque progression was observed, gene expression of IL-4 and chemokine (C-C motif) ligand 2 (Ccl2) was downregulated. In addition, 50 µg/Kg/day of both treatments was sufficient to inhibit circulating tumor necrosis factor alpha (TNF-α), interleukin-2 (IL-2) and interferon-gamma (IFN-γ) in serum. These results suggested that prodigiosin and undecylprodigiosin modulated inflammatory markers and could have an impact in reducing atherosclerotic plaque vulnerability.
Subject(s)
Atherosclerosis/immunology , Gene Expression Regulation/drug effects , Immunity/drug effects , Prodigiosin/analogs & derivatives , Receptors, LDL/physiology , Animals , Atherosclerosis/drug therapy , Atherosclerosis/pathology , Cytokines/metabolism , Immunosuppressive Agents/pharmacology , Lipids/blood , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Prodigiosin/pharmacologyABSTRACT
Polyphenols from diverse sources have shown anti-inflammatory activity. In the context of atherosclerosis, macrophages play important roles including matrix metalloproteinases synthesis involved in degradation of matrix extracellular components affecting the atherosclerotic plaque stability. We prepared a propolis extract and pinocembrin in ethanol solution. Propolis extract was chemically characterized using LC-MS. The effect of treatments on gene expression and proteolytic activity was measured in vitro using murine macrophages activated with LPS. Cellular toxicity associated with both treatments and the vehicle was determined using MTT and apoptosis/necrosis detection assays. MMP-9 gene expression and proteolytic activity were measured using qPCR and zymography, respectively. Thirty-two compounds were identified in the propolis extract, including pinocembrin among its major components. Treatment with either ethanolic extract of propolis or pinocembrin inhibits MMP-9 gene expression in a dose-dependent manner. Similarly, an inhibitory effect was observed in proteolytic activity. However, the effect showed by ethanolic extract of propolis was higher than the effect of pinocembrin, suggesting that MMP-9 inhibition results from a joint contribution between the components of the extract. These data suggest a potential role of polyphenols from Chilean propolis in the control of extracellular matrix degradation in atherosclerotic plaques.
Subject(s)
Flavanones/chemistry , Macrophages/drug effects , Macrophages/metabolism , Matrix Metalloproteinase 9/metabolism , Plaque, Atherosclerotic/metabolism , Polyphenols/chemistry , Animals , Apoptosis , Atherosclerosis/metabolism , Cell Survival , Chromatography, Liquid , Gene Expression Profiling , Lipopolysaccharides , Macrophage Activation , Mass Spectrometry , Mice , Necrosis , Polymerase Chain Reaction , Propolis/chemistry , RAW 264.7 CellsABSTRACT
PURPOSE: In general, the surface functionalization of polymeric nanoparticles is carried out by covalently bounding ligands to the nanoparticle surface. This process can cause a lack or decrease of the ligand specificity to its target receptor, besides the need of purification steps. We proposed a ligand-metal-chitosan-lecithin complex as a new strategy to functionalize the surface of biodegradable nanoparticles. METHODS: One pot synthesis of scFv anti-LDL(-)-functionalized nanocapsules was carried out by self-assembly and interfacial reactions. Particle sizing techniques, lipid peroxidation and molecular recognition by enzyme linked immuno sorbent assays were carried out. RESULTS: The selected formulation had unimodal size distribution with mean diameter of about 130 nm. The metals in the complex did not enhance the oxidative stress, and the scFv anti-LDL(-)-functionalized nanocapsules recognized LDL(-) and did not react with native LDL indicating the maintenance of the active site of the fragment. CONCLUSIONS: The one pot synthesis, using the ligand-metal-chitosan-lecithin complex to functionalize the surface of the biodegradable nanocapsules, maintained the active site of the antibody fragment making the device interesting for applications in nanomedicine.
Subject(s)
Lipoproteins, LDL/immunology , Nanocapsules/chemistry , Nanoparticles/chemistry , Polymers/chemistry , Single-Chain Antibodies/chemistry , Single-Chain Antibodies/immunology , Catalytic Domain , Chemistry, Pharmaceutical/methods , Chitosan/chemistry , Lecithins/chemistry , Ligands , Lipid Peroxidation/drug effects , Metals/chemistry , Oxidative Stress/drug effects , Particle SizeABSTRACT
New vessel formation plays a critical role in the progression and vulnerability of atherosclerotic lesions. It has been shown that polyphenols from propolis attenuate the progression of atherosclerosis and also exert inhibitory effects on angiogenic factors. However, the mechanisms underlying these effects are not completely understood. Thus, this study aimed to identify microRNAs (miRNAs) involved in the modulation of pro-angiogenic factors in the atherosclerotic plaques of LDL receptor gene knockout mice treated with a polyphenol-rich extract of Chilean propolis. The progression of the atherosclerotic lesions was significantly attenuated in treated mice compared with control mice. Using microarray analysis and a bioinformatic approach, we identified 29 differentially expressed miRNAs. Many of these miRNAs were involved in biological processes associated with angiogenesis, such as the cell cycle, cell migration, cell growth and proliferation. Among them, three miRNAs (miR-181a, miR-106a and miR-20b) were over-expressed and inversely related to the expression of Vegfa (vascular endothelial growth factor A) and Hif1a (hypoxia inducible factor 1 alpha). In addition, VEGF-A protein expression was attenuated in histological sections obtained from the aortic sinuses of treated mice. VEGFA is a key pro-angiogenic factor in atherosclerotic plaques, and Hif1a, which is expressed in the necrotic nucleus of the atheroma, is its main inducer. We found a correlation between the over-expression of miR-181a, miR-106a and miR-20b and their target genes, Hif1a and Vegfa, which is consistent with attenuation of the atherosclerotic lesion. In conclusion, our data analysis provides evidence that the anti-angiogenic effects of polyphenols from Chilean propolis can be modulated by miRNAs, in particular miR-181a, miR-106a and miR-20b.
Subject(s)
Angiogenesis Inducing Agents/pharmacology , Atherosclerosis/physiopathology , MicroRNAs/analysis , Polyphenols/pharmacology , Propolis/chemistry , Angiogenesis Inducing Agents/chemistry , Animals , Male , Mice , Polyphenols/chemistryABSTRACT
The in vivo modified forms of low-density lipoprotein (LDL) are important for the formation of foam cells and as mediators of the immuno-inflammatory process involved in the progression of atherosclerosis. Electronegative LDL, LDL(-), is a LDL subfraction with pro-inflammatory properties that is present in human blood. To investigate possible atheroprotective effects, an anti-LDL(-) single-chain variable fragment (scFv) was expressed in the methylotrophic yeast Pichia pastoris and its activity was evaluated in vitro against macrophages and in experimental atherosclerosis in Ldlr(-/-) mice. The recombinant 2C7 scFv was produced in a yield of 9.5 mg of protein/L. The specificity and affinity of purified 2C7 scFv against LDL(-) was confirmed by ELISA. To assess the activity of 2C7 scFv on foam cell formation, RAW 264.7 macrophages were exposed to LDL(-) in the presence or absence of 2C7 scFv. The 2C7 scFv inhibited the uptake of LDL(-) by macrophages in a dose-dependent manner, and internalization of LDL(-) by these cells was found to be mediated by the CD36 and CD14 receptor. In addition, compared with untreated cells, lipid accumulation in macrophages was decreased, and the expression of Cd36, Tlr-4 and Cox-2 was downregulated in macrophages treated with 2C7 scFv. Importantly, compared with untreated mice, the treatment of Ldlr(-/-) mice with 2C7 scFv decreased the atherosclerotic lesion area at the aortic sinus. In conclusion, our data show that 2C7 scFv inhibits foam cell formation and atherosclerotic plaque development by modulating the expression of genes relevant to atherogenesis. These results encourage further use of this antibody fragment in the development of new therapeutic strategies that neutralize the pro-atherogenic effects of LDL(-).
