A novel role of bone morphogenetic protein-7 in the regulation of adhesion and migration of human monocytic cells.

BACKGROUND: Bone morphogenetic protein (BMP) 7 is abundant in atherosclerotic plaques and increases monocyte pro-coagulant activity by enhancing tissue factor (TF) expression. While several members of the BMP superfamily are able to serve as chemotactic agents for monocytes, the role of BMP-7 in regulation of monocyte motility is not known. AIMS: To assess the effect of BMP-7 on adhesive and migratory properties of human monocytes. METHODS: Chemokinesis, adhesion, and transendothelial migration of BMP-7-treated THP-1 cells and human monocytes were analysed using live-cell imaging, orbital shear, and Boyden chamber assays. Surface presentation of ß2 integrins and phosphorylation status of Akt & focal adhesion kinase (FAK) were studied by flow cytometry and Western blot. RESULTS: High levels of BMP-7 protein were detectable in intimal regions of atherosclerotic plaques; BMP-7 significantly enhanced THP-1 and monocyte chemokinetic properties in vitro (1.21+0.01 and 1.76+0.21 fold increase in crawling distance, respectively). Under orbital shear, adhesion of monocytic cells to microvascular endothelial cell (MVEC) monolayers was also significantly increased by BMP-7 (3.89+1.56 and 2.57+0.97 fold over vehicle). Moreover, BMP-7 accelerated transendothelial migration of THP-1 cells and monocytes towards MCP-1 (5.91+0.88 and 2.96±0.65 fold increase, respectively). BMP-7 enhanced cell surface presentation of ß2 integrins in the active conformation. Observed effects were determined to be Akt and FAK dependent, as shown by pharmacological inhibition. CONCLUSION: BMP-7 directly upregulates adhesion and migration of human monocytic cells via activation of ß2 integrins, Akt, and FAK. Our findings suggest that BMP-7 may serve as a novel contributor to atherogenesis.

Isolation and characterization of the [Ga2Al18O8(OH)36(H2O)12](8+) cluster: cationic variations on the Wells-Dawson topology.

The structural chemistry of Group 13 polyoxometalates lags far behind related negatively charged transition metal species and limits the development of advanced materials. A novel heterometallic cluster [Ga2Al18O8(OH)36(H2O)12](8+) (Ga2Al18) has been isolated using a supramolecular approach and structurally characterized using single-crystal X-ray diffraction. Ga2Al18 represents the Wells-Dawson structure polycations and variations in the structural topology may be related to the initial stabilization of the Keggin isomer. DFT calculations on the related ε-Keggins (GaAl12 and Al13), Ga2Al18, and theoretical Al2Al18 clusters reveal similar features of electronic structure, suggesting additional heteroatom substitution in other isostructural clusters should be possible.

Procoagulant and proinflammatory effects of red blood cells on lipopolysaccharide-stimulated monocytes.

BACKGROUND: We aimed to evaluate the mechanisms underlying the effects of red blood cells (RBCs) on the reactivity of monocytes to lipopolysaccharide (LPS) stimulation. METHODS: Measurements of tissue factor (TF) antigen and activity were performed on freshly isolated white blood cells (WBCs)/platelets resuspended in heparinized plasma, as well as cultured monocytic cells. RESULTS: In a dose-dependent manner, RBCs significantly enhanced LPS-induced TF activity and antigen levels in blood monocytes; potentiation of TF activity by both human and murine RBCs did not require the presence of neutrophils and/or platelets. We also measured the levels of monocyte chemotactic protein-1 (MCP-1), the key proinflammatory chemokine that binds to duffy antigen receptor for chemokines (DARC) on RBC surface, in plasma and RBC lysates after the incubation of RBCs with WBC/platelets; at the concentrations corresponding to normal blood counts, RBCs exerted a significant influence on the free plasma levels of MCP-1, with about two-thirds of detectable MCP-1 post-LPS stimulation being associated with RBCs. Critically, DARC-deficient murine RBCs failed to enhance LPS-induced TF activity, confirming the mechanistic significance of RBC-DARC. CONCLUSIONS: Our study reports a novel mechanism by which RBCs promote procoagulant and proinflammatory sequelae of WBC exposure to LPS, likely mediated by RBC-DARC in the microenvironment(s) that bring monocytes and RBCs in close proximity.

Chemical controls on uranyl citrate speciation and the self-assembly of nanoscale macrocycles and sandwich complexes in aqueous solutions.

Uranyl citrate forms trimeric species at pH > 5.5, but exact structural characteristics of these important oligomers have not previously been reported. Crystallization and structural characterization of the trimers suggests the self-assembly of the 3 : 3 and 3 : 2 U : Cit complexes into larger sandwich and macrocyclic molecules. Raman spectroscopy and ESI-MS have been utilized to investigate the relative abundance of these species in solution under varying pH and citrate concentrations. Additional dynamic light scattering experiments indicate that self-assembly of the larger molecules does occur in aqueous solution.

BMP-7 induces TF expression in human monocytes by increasing F3 transcriptional activity.

BACKGROUND: Bone morphogenetic protein (BMP)-7, a major regulator of bone metabolism, inhibits ectopic calcification in atherosclerotic plaques. We have recently reported that BMP-7 is also a potent inducer of tissue factor (TF) in human mononuclear cells (MNCs). While nuclear factor kappa beta (NF-kB) and activation protein-1 (AP-1) are the transcription factors essential for inducible expression of human TF gene (F3), the mechanisms responsible for TF induction by BMP-7 are not known. OBJECTIVE: To elucidate the molecular mechanisms governing BMP-7-triggered TF expression in human MNCs. METHODS: Human blood monocytes were stimulated with BMP-7 and western blotting, qRT-PCR, and flow cytometry studies were carried out to assess F3 expression; promoter studies were also performed using a panel of reporter constructs. Procoagulant TF activity was measured using a validated FXa generation assay. The significance of NF-kB transcriptional activity was verified via pharmacological inhibition. RESULTS: BMP-7 increased TF protein levels, procoagulant activity, surface presentation, and TF mRNA expression. This increase was accompanied by activation of NF-kB as evidenced by reduced IkB-α levels and elevated transcriptional activity of an NF-kB-sensitive reporter in transfected MNCs. Although treatment with BMP-7 also led to a strong phosphorylation of c-Jun, activation of AP-1 alone was not sufficient to induce TF expression: JSH-23, a potent and specific NF-kB inhibitor, completely blocked BMP-7-induced TF expression. CONCLUSIONS: We report that BMP-7-dependent activation of TF in human MNCs is mediated via increased activity of NF-kB, leading to enhanced F3 transcription in human MNCs.

Microparticle association and heterogeneity of tumor-derived tissue factor in plasma: is it important for coagulation activation?

BACKGROUND: Tumor-derived tissue factor (TF) activates coagulation in vitro and in vivo in an orthotopic model of human pancreatic cancer. Here, we further characterized tumor-derived TF in this model. METHODS: Conditioned medium (CM) of L3.6pl human pancreatic tumor cells and plasma from nude mice bearing L3.6pl tumors were ultracentrifuged, and the pellets were filtered through membranes with different pore sizes. The size distribution of particles was analyzed in CM or plasma fractions with nanoparticle tracking and dynamic light scattering. Human TF antigen and activity were measured in pellets and supernatants with ELISA and clotting or thrombin generation assays, respectively. Human alternatively spliced TF (asTF) was measured with ELISA. Human TF and thrombin-antithrombin complex (TAT) concentrations were assessed in plasma of mice injected with filtered fractions of CM. RESULTS: Particles in both CM and plasma were < 0.4 µm. TF antigen and activity in the CM were mainly associated with microparticles (MP). Approximately 50% of antigen and 20% of activity were associated with particles of < 0.1 µm. Injection of < 0.1 µm particles into mice caused a 30% drop in platelet counts and an increase in TAT levels. In contrast, ~ 90% of TF antigen in tumor-bearing mice plasmas was non-sedimentable, whereas TF activity was exclusively associated with MP. Particles of < 0.1 µm and the supernatants of both CM and plasma gained TF activity after addition of exogenous phospholipids. Although asTF was found in MP-free CM supernatants, it was also present in CM and plasma pellets. CONCLUSIONS: Tumor-derived particles of < 0.1 µm and non-sedimentable TF are or can become procoagulant in the presence of phospholipids, and may contribute to the procoagulant potential of circulating TF.

Effects of flue gas composition on the catalytic destruction of chlorinated aromatic compounds with a V-oxide catalyst.

When using catalytic flue gas cleaning, several flue gas compounds may influence oxidation reactions of hazardous volatile organic compounds, possibly leading to lower reaction rates and, thus, to an incomplete destruction. Experimental investigations were performed with regard to the influence of selected flue gas compounds, like hydrogen chloride, sulfur dioxide, oxygen, and water vapour, on the catalytic destruction behavior of chlorobenzenes under flue gas cleaning conditions of an incineration plant. For this purpose, a metal oxide catalyst was operated at different temperatures at a space velocity of 3600 h-1 in a laboratory-scale fixed bed reactor with model flue gases, and with real flue gases generated from the TAMARA waste incineration plant. The results obtained from the studies with model flue gas were analyzed with respect to reaction kinetics. These kinetics were applied for comparison with the experimental data gained in the real flue gas.

Parasites of dogs from Indian settlements in northwestern Canada: a survey with public health implications.

A total of 959 faecal samples were obtained from dogs in 12 native communities in Northern Saskatchewan, Central and Northern Alberta and the Northwest Territories. All samples were examined using a flotation technique. Samples from an area of endemic human amoebic infections were also examined by a formol-ether sedimentation method. Eighteen necropsies were performed. Entamoeba histolytica cysts were recovered from dog faeces at Loon Lake, Saskatchewan. Toxocara canis had low incidence in Saskatchewan and Central Alberta, and appeared to be almost non-existent further North. Toxascaris leonina was found in all areas surveyed. Canine hookworm infections were plentiful in all areas, the highest incidence being recorded from Northern Alberta and Northwest Territories. Many Taenia (or Echinococcus) infections were found consistently in all areas. Only one infection with Dipylidium caninum was discovered.Metorchis conjunctus infections were found to be common in the Saskatchewan reserves. Infections with Diphyllobothrium sp. were found in all communities with access to good fishing. One specimen of Dioctophyma renale was recovered at necropsy. Infections with parasites of no known zoonotic importance such as Trichuris, Alaria and Isospora species were also recorded.