Collectively, these results indicate that RT could be a candidate therapeutic agent for treatment of various severe vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Cudratricusxanthone A (CTXA), a natural bioactive compound extracted from the roots of Cudrania tricuspidata Bureau, is known to possess hepatoprotective, antiproliferative and anti-inflammatory activities. However, antiplatelet, anticoagulant, and profibrinolytic properties have not been studied. The anticoagulant activities of CTXA were measured by monitoring activated partial thromboplastin-time (aPTT), prothrombin time (PT), and the activities of cell-based thrombin and activated factor X (FXa). The effects of CTXA on the expressions of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were also tested in tumor necrosis factor-α (TNF-α) activated human umbilical vein endothelial cells. Our data showed that CTXA inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation, prolonged aPTT and PT significantly and inhibited the activities and production of thrombin and FXa. CTXA prolonged in vivo bleeding time and inhibited TNF-α induced PAI-1 production. Furthermore, PAI-1/t-PA ratio was significantly decreased by CTXA. Collectively, these results indicate that CTXA possesses antithrombotic activities and suggest that the current study could provide bases for the development of new anticoagulant agents.

No abstract

High mobility group box-1 (HMGB1) protein acts as a late mediator of severe vascular inflammatory conditions. Orientin has been known to have anxiolytic and antioxidative activities. However, the effect of orientin on HMGB1-induced inflammatory response has not been studied. We assessed this question by monitoring the effects of post-treatment orientin and its derivatives on lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated regulation of pro-inflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice. Post-treatment orientin was found to suppress LPS-mediated release of HMGB1 and HMGB1-mediated cytoskeletal rearrangements. Orientin inhibited HMGB1-mediated hyperpermeability and leukocyte migration in septic mice. Orientin also induced down-regulation of CLP-induced release of HMGB1 and mortality. Collectively, these results suggest that orientin may be regarded as a candidate therapeutic agent for treatment of vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

No abstract

Natural and synthetic unsaturated glucuronides were tested as substrates for Clostridium perfringens unsaturated glucuronyl hydrolase to probe its mechanism and to guide inhibitor design. Of the natural substrates, a chondroitin disaccharide substrate with sulfation of the primary alcohol on carbon 6 of its N-acetylgalactosamine moiety was found to have the highest turnover number of any substrate reported for an unsaturated glucuronyl hydrolase, with kcat =112 s(-1) . Synthetic aryl glycoside substrates with electron-withdrawing aglycone substituents were cleaved more slowly than those with electron-donating substituents. Similarly, an unsaturated glucuronyl fluoride was found to be a particularly poor substrate, with kcat /Km =44 nM(-1) s(-1) -a very unusual result for a glycoside-cleaving enzyme. These results are consistent with a transition state with positive charge at carbon 5 and the endocyclic oxygen, as anticipated in the hydration mechanism proposed. However, several analogues designed to take advantage of strong enzyme binding to such a transition state showed little to no inhibition. This result suggests that further work is required to understand the true nature of the transition state stabilised by this enzyme.

Background: Unsaturated glucuronyl hydrolases (UGL) from GH88 are bacterial enzymes involved in the degradation of glycosaminoglycans and are virulence factors. Results: Mechanistic data inconsistent with the currently accepted mechanism of UGL are presented. Conclusion: A revised mechanism is proposed to explain all mechanistic data published to date. Significance: Understanding of the mechanism of UGL may allow design of bacteriostatic agents.

The development of new sepsis-specific biomarkers is mandatory to improve the detection and monitoring of the disease. Hemoglobin is the main oxygen and carbon dioxide carrier in cells of the erythroid lineage and is responsible for oxygen delivery to the respiring tissues of the body. Hemoglobin subunit beta (HBβ) is a component of a larger protein called hemoglobin. The aim of this study was to evaluate blood levels of HBβ in septic patients. A prospective study of 82 patients with sepsis was conducted. Furthermore, C57BL/6 mice were subjected to cecal ligation and puncture (CLP) surgery. Alternatively, human umbilical vein endothelial cells (HUVECs) or C57BL/6 mice were exposed to lipopolysaccharide (LPS, 100 ng/ml to HUVECs or 10 mg/kg to mice). The data showed that LPS induced upregulation of the synthesis and secretion of HBβ in LPS-treated HUVECs and in LPS-injected and CLP mice. In patients admitted to the intensive care unit with sepsis, circulating levels of HBβ were significantly high (sepsis, 64.93-114.76 ng/ml, n = 30; severe sepsis, 157.37-268.69 ng/ml, n = 22; septic shock, 309.98-427.03 ng/ml, n = 30) when compared to the levels of control donors (9.76-12.28 ng/ml, n = 21). Patients with septic shock had higher HBβ levels when compared to patients with severe sepsis. Furthermore, the HBβ levels in septic patients were higher than those in healthy volunteers. These results suggest that in septic patients, HBβ blood level is related to the severity of sepsis and may represent a novel endothelial cell dysfunction marker. Moreover, HBβ can be used as a biomarker to determine the severity of sepsis.