Transforming growth factor β-induced protein promotes severe vascular inflammatory responses

Endothelial STAT3 Activation Increases Vascular Leakage Through Downregulating Tight Junction Proteins: Implications for Diabetic Retinopathy

Vascular inflammation is characteristic feature of diabetic retinopathy. In diabetic retina, a variety of the pro-inflammatory cytokines are elevated and involved in endothelial dysfunction. STAT3 transcription factor has been implicated in mediating cytokine signaling during vascular inflammation. However, whether and how STAT3 is involved in the direct regulation of the endothelial permeability is currently undefined. Our studies revealed that IL-6-induced STAT3 activation increases retinal endothelial permeability and vascular leakage in retinas of mice through the reduced expression of the tight junction proteins ZO-1 and occludin. In a co-culture model with microglia and endothelial cells under a high glucose condition, the microglia-derived IL-6 induced STAT3 activation in the retinal endothelial cells, leading to increasing endothelial permeability. In addition, IL-6-induced STAT3 activation was independent of ROS generation in the retinal endothelial cells. Moreover, we demonstrated that STAT3 activation downregulates the ZO-1 and occludin levels and increases the endothelial permeability through the induction of VEGF production in retinal endothelial cells. These results suggest the potential importance of IL-6/STAT3 signaling in regulating endothelial permeability and provide a therapeutic target to prevent the pathology of diabetic retinopathy. J. Cell. Physiol. 232: 1123-1134, 2017. © 2016 Wiley Periodicals, Inc.

Inhibitory Effect of Three Diketopiperazines from Marine-derived Bacteria on Secretory Group IIA Phospholipase A2

Diketopiperazines, natural products found in bacteria, fungi, marine sponges, gorgonian and red algae, are cyclic dipeptides possessing relatively simple and rigid structures with chiral nature and various side chains. The compounds in this structure class have been known to possess diverse bioactivities including antibiotic activity, anti-cancer activity, neuroprotective activity, and anti-inflammatory activity. The expression of secretory group IIA phospholipase A2 (sPLA2-IIA) is enhanced by development of inflammatory disorders. Aim of this study is to determine the effects of diketopiperazines on the secretion and activity of sPLA2-IIA by lipopolysaccharide (LPS) in human umbilical vein endothelial cells (HUVECs). To do this, sPLA2-IIA expression was induced in the LPS-stimulated HUVECs and mice to evaluate the effect of diketopiperazines. Results showed that diketopiperazines remarkably suppressed the LPS-mediated protein expression and activity of sPLA2-IIA via inhibition of phosphorylation of cytosolic phospholipase A2 (cPLA2) and extracellular signal-regulated kinase (ERK) 1/2. These results demonstrated that diketopiperazines might play an important role in the modulation of sPLA2-IIA expression and activity in response to the inflammatory diseases.

Ameliorative Effect of Vicenin-2 and Scolymoside on TGFBIp-Induced Septic Responses

Transforming growth factor β-induced protein (TGFBIp) is an extracellular matrix protein whose expression in several cell types is greatly increased by TGF-β. TGFBIp is released by the human umbilical vein endothelial cells (HUVECs) and functions as a mediator of experimental sepsis. Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain in biological processes. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, two active compounds in C. subternata against TGFBIp-mediated septic responses in HUVECs and mice. The anti-inflammatory activities of vicenin-2 or scolymoside were determined by measuring permeability, human neutrophils adhesion and migration, and activation of pro-inflammatory proteins in TGFBIp-activated HUVECs and mice. According to the results, vicenin-2 or scolymoside effectively inhibited lipopolysaccharide-induced release of TGFBIp and suppressed TGFBIp-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, vicenin-2 or scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6 and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by TGFBIp. Vicenin-2 or scolymoside reduced cecal ligation and puncture (CLP)-induced septic mortality and pulmonary injury. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agent for treatment of various severe vascular inflammatory diseases via inhibition of the TGFBIp signaling pathway.

Antitcoagulant and antiplatelet activities of scolymoside

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain. Here, the anticoagulant effects of scolymoside, an active compound in C. subternata, were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). The effects of scolymoside on plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) expression were evaluated in tumor necrosis factor (TNF)-α-activated human endothelial cells. Treatment with scolymoside resulted in prolonged aPTT and PT and the inhibition of thrombin and FXa activities and production. In addition, scolymoside inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. Scolymoside also elicited anticoagulant effects in mice, including a significant reduction in the PAI-1 to t-PA ratio. Collectively, these findings indicate that scolymoside possesses anticoagulant activities and could be developed as a novel anticoagulant.

Inhibitory effects of lysozyme on endothelial protein C receptor shedding in vitro and in vivo

Lysozyme protects us from the ever-present danger of bacterial infection and binds to bacterial lipopolysaccharide (LPS) with high affinity. Beyond its role in the activation of protein C, the endothelial cell protein C receptor (EPCR) plays an important role in the cytoprotective pathway. EPCR can be shed from the cell surface, which is mediated by tumor necrosis factor-α converting enzyme (TACE). However, little is known about the effects of lysozyme on EPCR shedding. We investigated this issue by monitoring the effects of lysozyme on phorbol-12-myristate 13-acetate (PMA)-, tumor necrosis factor (TNF)-α-, interleukin (IL)-1βand cecal ligation and puncture (CLP)-mediated EPCR shedding and underlying mechanism. Data demonstrate that lysozyme induced potent inhibition of PMA-, TNF-α-, IL-1β-, and CLP-induced EPCR shedding. Lysozyme also inhibited the expression and activity of PMA-induced TACE in endothelial cells. These results demonstrate the potential of lysozyme as an anti-EPCR shedding reagent against PMA-mediated and CLP-mediated EPCR shedding. [BMB Reports 2015; 48(11): 624-629]

Suppressive effects of methylthiouracil on polyphosphate-mediated vascular inflammatory responses

Drug repositioning is used to discover drug candidates to treat human diseases, through the application of drugs or compounds that are approved for the treatment of other diseases. This method can significantly reduce the time required and cost of discovering new drug candidates for human diseases. Previous studies have reported pro‐inflammatory responses of endothelial cells to the release of polyphosphate (PolyP). In this study, we examined the anti‐inflammatory responses and mechanisms of methylthiouracil (MTU), which is an antithyroid drug, and its effects on PolyP‐induced septic activities in human umbilical vein endothelial cells (HUVECs) and mice. The survival rates, septic biomarker levels, behaviour of human neutrophils and vascular permeability were determined in PolyP‐activated HUVECs and mice. MTU suppressed the PolyP‐mediated vascular barrier permeability, up‐regulation of inflammatory biomarkers, adhesion/migration of leucocytes, and activation and/or production of nuclear factor‐κB, tumour necrosis factor‐α and interleukin‐6. Furthermore, MTU demonstrated protective effects on PolyP‐mediated lethal death and the levels of the related septic biomarkers. Therefore, these results indicated the therapeutic potential of MTU on various systemic inflammatory diseases, such as sepsis or septic shock.

Suppressive Effects of Pelargonidin on Endothelial Protein C Receptor Shedding via the Inhibition of TACE Activity and MAP Kinases

Beyond its role in the activation of protein C, the endothelial cell protein C receptor (EPCR) plays an important role in the cytoprotective pathway. EPCR can be shed from the cell surface, which is mediated by tumor necrosis factor-[Formula: see text] converting enzyme (TACE). Pelargonidin is a well-known red pigment found in plants, and has been reported to have important biological activities that are potentially beneficial to human health. However, little is known about the effects of pelargonidin on EPCR shedding. We investigated this issue by monitoring the effects of pelargonidin on phorbol-12-myristate 13-acetate (PMA)-, tumor necrosis factor (TNF)-[Formula: see text]-, interleukin (IL)-1β-, and cecal ligation and puncture (CLP)-mediated EPCR shedding and by investigating the underlying mechanism of pelargonidin action. Data demonstrate that pelargonidin induced potent inhibition of PMA-, TNF-[Formula: see text]-, IL-1β-, and CLP-induced EPCR shedding by inhibiting the phosphorylation of mitogen-activated protein kinases (MAPKs) such as p38, janus kinase (JNK), and extracellular signal-regulated kinase (ERK) 1/2. Pelargonidin also inhibited the expression and activity of PMA-induced TACE in endothelial cells. These results demonstrate the potential of pelargonidin as an anti-EPCR shedding reagent against PMA- and CLP-mediated EPCR shedding.

Antithrombotic and antiplatelet activities of vicenin-2

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain in physiological processes. However, there are limited modern data on its pharmacological effects and active components relating to its traditional use. Here, the anticoagulant and antiplatelet activities of vicenin-2 (VCN), an active compound in C. subternata, were determined. The anticoagulant activities were investigated by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). The effects of VCN on the expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor (TNF)-α-activated human umbilical vein endothelial cells (HUVECs). Treatment with VCN resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, as well as inhibited production of thrombin and FXa in HUVECs. In addition, VCN inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. VCN also elicited anticoagulant effects in mice. In addition, treatment with VCN resulted in significant reduction of the PAI-1 to t-PA ratio. Collectively, VCN possesses antithrombotic activities and offers a basis for development of a novel anticoagulant.

Antiseptic Effects of New 3'-N-Substituted Carbazole Derivatives In Vitro and In Vivo

Inhibition of high-mobility group box 1 (HMGB1) protein and restoration of endothelial integrity are emerging as attractive therapeutic strategies in the management of sepsis. Here, new five structurally related 3'-N-substituted carbazole derivatives were examined for their effects on lipopolysaccharide (LPS)-mediated or cecal ligation and puncture (CLP)-mediated release of HMGB1 and on modulation of HMGB1-mediated inflammatory responses. We accessed this question by monitoring the effects of posttreatment carbazole derivatives on LPS- and CLP-mediated release of HMGB1 and HMGB1-mediated regulation of proinflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice. The new 3'-N-substituted carbazole derivatives 1-5 inhibited the release of HMGB1 and downregulated HMGB1-dependent inflammatory responses in human endothelial cells. New compounds also inhibited HMGB1-mediated hyperpermeability and leukocyte migration in mice. In addition, treatment with each compound reduced CLP-induced release of HMGB1 and sepsis-related mortality and pulmonary injury in mice. These results indicate that the new 3'-N-substituted carbazole derivatives could be candidate therapeutic agents for various severe vascular inflammatory diseases owing to their inhibition of the HMGB1 signaling pathway.

Inhibiting Integrin αvβ5 Reduces Ischemia-Reperfusion Injury in an Orthotopic Lung Transplant Model in Mice

Primary graft dysfunction after lung transplantation is the leading cause of morbidity and mortality in the immediate posttransplant period and is characterized by endothelial and epithelial barrier disruption and the leakage of protein-rich edema fluid. Integrins are cell surface receptors that have an important role in maintenance of the cell barrier, and inhibition of integrins, such as αvβ5, can diminish alveolar flooding in lung injury models. We hypothesized that inhibition of αvβ5 during donor lung cold ischemia would reduce endothelial permeability during reperfusion. Using an orthotopic single lung transplantation model with and without cold ischemia, donor lungs were perfused with αvβ5-blocking antibody (ALULA) or control antibody at the time of collection, followed by transplantation, 8 h of reperfusion, and the measurement of lung injury parameters. Prolonged cold ischemia (18 h) produced increases in extravascular lung water, protein permeability, and neutrophilic alveolitis and decreased oxygenation compared with lungs without cold ischemia. Perfusion of lungs with αvβ5 antibody versus control antibody protected donor lungs from injury and significantly improved oxygenation. In summary, αvβ5 integrin blockade protects from the development of ischemia-reperfusion lung injury and is a promising approach to preventing primary graft dysfunction in human lung transplant procedures.

Inhibitory effects of three diketopiperazines from marine-derived bacteria on endothelial protein C receptor shedding in human endothelial cells and mice

Diketopiperazine is a natural products found from bacteria, fungi, marine sponges, gorgonian and red algae. They are cyclic dipeptides possessing relatively simple and rigid structures with chiral nature and various side chains. The compounds in this structure class have been known to possess diverse bioactivities including antibiotic activity, anti-cancer activity, neuroprotective activity, and anti-inflammatory activity. The endothelial cell protein C receptor (EPCR) plays an important role in the cytoprotective pathway and in the activation of protein C. Endothelial cell protein C receptor (EPCR) can be shed from the cell surface, which is mediated by tumor necrosis factor-α converting enzyme (TACE). However, little is known about the effects of diketopiperazine on EPCR shedding. We investigated this issue by monitoring the effects of diketopiperazine on phorbol-12-myristate 13-acetate (PMA)-, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β-induced EPCR shedding in human umbilical vein endothelial cells (HUVECs), and cecal ligation and puncture (CLP)-mediated EPCR shedding in mice and underlying mechanism. Here, three (1-3) of diketopiperazines were isolated from two strains of marine-derived bacteria and 1-3 induced potent inhibition of PMA-, TNF-α-, IL-1β (in HUVECs), and CLP-induced EPCR shedding (in mice) via inhibition of phosphorylation of mitogen-activated protein kinases (MAPKs) such as p38, janus kinase (JNK), and extracellular signal-regulated kinase (ERK) 1/2. 1-3 also inhibited the expression and activity of PMA-induced TACE in HUVECs suggesting that p38, ERK1/2, and JNK could be molecular targets of 1-3. These results demonstrate the potential of 1-3 as an anti-EPCR shedding reagent against PMA-mediated and CLP-mediated EPCR shedding.

Vicenin-2 and scolymoside inhibit high-glucose-induced vascular inflammation in vitro and in vivo

The vascular inflammatory process has been suggested to play a key role in the initiation and progression of atherosclerosis, a major complication of diabetes mellitus. Thus, in this study, we attempted to determine whether 2 structurally related flavonoids found in Cyclopia subternata, vicenin-2 and scolymoside, can suppress high-glucose (HG)-induced vascular inflammatory processes in human umbilical vein endothelial cells (HUVECs) and mice. The effects of vicenin-2 and scolymoside on HG-induced vascular inflammation were determined by measuring vascular permeability, leukocyte adhesion and migration, cell adhesion molecule (CAM) expression levels, and reactive oxygen species (ROS) formation. In addition, the anti-inflammation mechanism was investigated using immunofluorescence staining and Western blotting. The data showed that HG markedly increased vascular permeability, monocyte adhesion, expression of CAMs, formation of reactive oxygen species (ROS), and activation of nuclear factor (NF)-κB. Remarkably, pretreatment with vicenin-2 and scolymoside attenuated all of the above-mentioned vascular inflammatory effects of HG. HG-induced vascular inflammatory responses are critical events underlying the development of various diabetic complications; therefore, our results suggest that vicenin-2 and scolymoside have significant therapeutic benefits against diabetic complications and atherosclerosis.

Antithrombotic and antiplatelet activities of small-molecule alkaloids from Scolopendra subspinipes mutilans

The aim of this study was to discover small-molecule anticoagulants from Scolopendra subspinipes mutilans (SSM). A new acylated polyamine (1) and a new sulfated quinoline alkaloid (2) were isolated from SSM. Treatment with the new alkaloids 1, 2, and indole acetic acid 4 prolonged the activated partial thromboplastin time and prothrombin time and inhibited the activity and production of thrombin and activated factor X. Furthermore, compounds 1, 2, and 4 inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. In accordance with these potential in vitro antiplatelet activities, compounds 1, 2, and 4 showed enhanced antithrombotic effects in an in vivo pulmonary embolism and arterial thrombosis model. Compounds 1, 2, and 4 also elicited anticoagulant effects in mice. Collectively, this study may serve as the groundwork for commercializing SSM or compounds 1, 2, and 4 as functional food components for the prevention and treatment of pathogenic conditions and serve as new scaffolds for the development of anticoagulants.

Inhibitory Effect of FXa on Secretory Group IIA Phospholipase A2

It is well known that the expression level of secretory group IIA phospholipase A2 (sPLA2-IIA) is elevated in inflammatory diseases and lipopolysaccharide (LPS) upregulates the expression of sPLA2-IIA in human umbilical vein endothelial cells (HUVECs). Activated factor X (FXa) is an important enzyme in the coagulation cascade responsible for thrombin generation, and it influences cell signaling in various cell types by activating protease-activated receptors (PARs). Here, FX or FXa was examined for its effects on the expression and activity of sPLA2-IIA in HUVECs and mouse. Prior treatment of cells or mouse with FXa inhibited LPS-induced expression and activity of sPLA2-IIA via interacting with FXa receptor (effective cell protease receptor-1, EPR-1). And FXa suppressed the activation of cytosolic phospholipase A2 (cPLA2) and extracellular signal-regulated kinase (ERK) 1/2 by LPS. Therefore, these results suggest that FXa may inhibit LPS-mediated expression of sPLA2-IIA by suppression of cPLA2 and ERK 1/2.

Antithrombotic and antiplatelet activities of pelargonidin in vivo and in vitro

Pelargonidin is a well-known red pigment found in plants, and has been reported as having important biological activities that are potentially beneficial for human health. However, the possible roles of pelargonidin as an anticoagulant and the underlying mechanism have not yet been elucidated. We tested the effect of pelargonidin and its glucoside-conjugated form, pelargonidin-3-glucoside, on the clotting times, such as activated partial thromboplastin time (aPTT) and prothrombin time (PT), and the activities and productions of thrombin and activated factor X (FXa). Furthermore, the effects of pelargonidin on the fibrin polymerization, platelet aggregation, and the ratio of plasminogen activator inhibitor-1 (PAI-1) to tissue plasminogen activator were determined. Pelargonidin, but not pelargonidin-3-glucoside, prolonged the aPTT and PT, and inhibited the activity and production of thrombin and FXa in human umbilical vein endothelial cells. Furthermore, pelargonidin inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation and elicited anticoagulant effects in mice. In addition, pelargonidin significantly reduced PAI-1 to t-PA ratio. Collectively, these results indicate that the anthocyanin pelargonidin possesses antithrombotic activity, and can be beneficial in preventing thrombus formation, thus improving blood circulation.

Suppressive effects of polyozellin on TGFBIp-mediated septic responses in human endothelial cells and mice

Polyozellus multiplex (Thelephoraceae) is a wild mushroom in Korea and Japan and is usually harvested in early autumn for food. Polyozellin, a major constituent of the edible mushroom P multiplex, has been known to exhibit biological activities such as antioxidative and anti-inflammatory effects. Transforming growth factor β-induced protein (TGFBIp) is an extracellular matrix protein whose expression in several cell types is greatly increased by TGF-β. TGFBIp is released by human umbilical vein endothelial cells and functions as a mediator of experimental sepsis. We hypothesized that polyozellin could reduce TGFBIp-mediated severe inflammatory responses in human endothelial cells and mice. Here, we investigated the antiseptic effects and underlying mechanisms of polyozellin against TGFBIp-mediated septic responses. Polyozellin effectively inhibited lipopolysaccharide-induced release of TGFBIp and suppressed TGFBIp-mediated septic responses. In addition, polyozellin suppressed cecal ligation and puncture-induced sepsis lethality and pulmonary injury. In conclusion, polyozellin suppressed TGFBIp-mediated and cecal ligation and puncture-induced septic responses. Therefore, polyozellin could be a potential therapeutic agent for treatment of various severe vascular inflammatory diseases via inhibition of the TGFBIp signaling pathway.

Inhibitory effect of polyozellin on secretory group IIA phospholipase A2

The expression of secretory group IIA phospholipase A2 (sPLA2-IIA) is enhanced by development of inflammatory disorders. In this study, sPLA2-IIA expression was induced in the lipopolysaccharide (LPS)-stimulated human umbilical vein endothelial cells and mice to evaluate the effect of polyozellin. Polyozellin, a major constituent of a Korea edible mushroom Polyozellus multiplex, has been known to exhibit the biological activities such as anti-oxidative and anti-inflammatory effects. Polyozellin remarkably suppressed the LPS-mediated protein expression and activity of sPLA2-IIA via inhibition of phosphorylation of cytosolic phospholipase A2 and extracellular signal-regulated kinase 1/2. These results demonstrated that polyozellin might play an important role in the modulation of sPLA2-IIA expression and activity in response to the inflammatory diseases.

Suppressive effects of polyozellin on endothelial protein C receptor shedding via inhibiting TACE activity and MAP kinases

Beyond its role in the activation of protein C, the endothelial cell protein C receptor (EPCR) plays an important role in the cytoprotective pathway. EPCR can be shed from the cell surface, which is mediated by tumor necrosis factor-α converting enzyme (TACE). Polyozellin, a major constituent of a Korea edible mushroom Polyozellus multiplex, has been known to exhibit the biological activities such as anti-oxidative and anti-inflammatory effects. However, little is known about the effects of polyozellin on EPCR shedding. We investigated this issue by monitoring the effects of polyozellin on phorbol-12-myristate 13-acetate (PMA)-, tumor necrosis factor (TNF)-α-, interleukin (IL)-1β-induced EPCR shedding in human umbilical vein endothelial cells (HUVECs), and cecal ligation and puncture (CLP)-mediated EPCR shedding in mice and underlying mechanism. Data demonstrate that polyozellin induced potent inhibition of PMA-, TNF-α-, IL-1β- (in HUVECs), and CLP-induced EPCR shedding (in mice) via inhibition of phosphorylation of mitogen-activated protein kinases (MAPKs) such as p38, janus kinase (JNK), and extracellular signal-regulated kinase (ERK) 1/2. Polyozellin also inhibited the expression and activity of PMA-induced TACE in HUVECs suggesting that p38, ERK1/2, and JNK could be the molecular targets of POZ. These results demonstrate the potential of polyozellin as an anti-EPCR shedding reagent against PMA-mediated and CLP-mediated EPCR shedding.

In-depth proteomics approach of secretome to identify novel biomarker for sepsis in LPS-stimulated endothelial cells

Sepsis and septic shock, which are conditions triggered by infection, occur with high incidence in emergency departments and are among the most common causes of death in hospitalized patients worldwide. Therefore, the identification of sepsis biomarkers for the rapid diagnosis is a major goal for researchers in the field of critical care. Endothelial cells play a pivotal role in orchestrating the inflammatory response triggered by sepsis. In this study, we used proteomics to investigate the secretome of EA.hy926 endothelial cells following lipopolysaccharide (LPS) stimulation with 1 μg/mL LPS for 12 or 24 h. SILAC in cell cultures and an online 2D-LC-MS/MS system were used to analyze the secretome dynamics in response to LPS. We found that 22 of the 77 secreted proteins identified in both the presence and absence of LPS and that 19 of the secreted proteins were quantified more strongly after LPS treatment for 24 h than after treatment for 12 h. By Gene Ontology and KEGG pathway analyses, we found that proteins related to the regulation of the actin cytoskeleton showed the highest secretion response to LPS stimulation. Out of the 19 candidate proteins, we focused on moesin, which is involved in the function of endothelial cells, and confirmed its amount in cellular lysates and media taken from primary human umbilical vein endothelial cells treated with LPS. To our knowledge, this study provides the first in-depth analysis of the LPS-induced secretome in human endothelial cells, and we propose 19 new biomarker candidates for sepsis, including moesin.

Ameliorative Effect of Aspalathin and Nothofagin from Rooibos (Aspalathus linearis) on HMGB1-Induced Septic ResponsesIn VitroandIn Vivo

The ubiquitous nuclear protein, high mobility group box 1 (HMGB1), is released by activated macrophages and human umbilical vein endothelial cells (HUVECs) and functions as a late mediator of experimental sepsis. Aspalathin (Asp) and nothofagin (Not), which have been reported to have anti-oxidant activity, are the two major active dihydrochalcones found in green rooibos. In this study, we investigated the antiseptic effects and underlying mechanisms of Asp and Not against HMGB1-mediated septic responses in HUVECs and mice. The anti-inflammatory activities of Asp and Not were determined by measuring permeability, monocyte adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice. According to the results, Asp and Not effectively inhibited lipopolysaccharide (LPS)-induced release of HMGB1, and suppressed HMGB1-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, Asp and Not suppressed the production of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), the activation of nuclear factor-κB (NF-κB) and extracellular signal-regulated kinases 1 and 2 (ERK1/2) by HMGB1. Collectively, these results indicate that Asp and Not could be potential therapeutic agents for the treatment of various severe vascular inflammatory diseases via the inhibition of the HMGB1 signaling pathway.

Periostin and TGF-β-induced protein: Two peas in a pod?

Periostin (PN) and TGF-β-induced protein (βig-h3) are paralogs that contain a single emilin and four fasciclin-1 modules and are secreted from cells. PN receives attention because of its up-regulation in cancer and degenerative and allergic diseases. βig-h3 is highly enriched in cornea and best known for harboring mutations in humans associated with corneal dystrophies. Both proteins are expressed widely, and many functions, some over-lapping, have been attributed to PN and βig-h3 based on biochemical, cell culture, and whole animal experiments. We attempt to organize this knowledge so as to facilitate research on these interesting and incompletely understood proteins. We focus particularly on whether PN and βig-h3 are modified by vitamin K-dependent γ-glutamyl carboxylation, a question of considerable importance given the profound effects of γ-carboxylation on structure and function of other proteins. We consider the roles of PN and βig-h3 in formation of extracellular matrix and as ligands for integrin receptors. We attempt to reconcile the contradictory results that have arisen concerning the role of PN, which has emerged as a marker of TH2 immunity, in murine models of allergic asthma. Finally, when possible we compare and contrast the structures and functions of the two proteins.

Methylthiouracil, a new treatment option for sepsis

The screening of bioactive compound libraries can be an effective approach for repositioning FDA-approved drugs or discovering new treatments for human diseases. Inhibition of high mobility group box 1 (HMGB1) and restoration of endothelial integrity are emerging as an attractive therapeutic strategies in the management of severe sepsis or septic shock. Here, we examined the effects of methylthiouracil (MTU), used as antithyroid drug, by monitoring the effects on lipopolysaccharide (LPS)- or cecal ligation and puncture (CLP)-mediated release of HMGB1, and on the modulation of HMGB1-mediated inflammatory responses. The anti-inflammatory activities of MTU were determined by measuring permeability, leukocyte adhesion and migration, and the activation of pro-inflammatory proteins in HMGB1-activated HUVECs and mice. MTU inhibited the release of HMGB1 and downregulated HMGB1-dependent inflammatory responses in human endothelial cells. MTU also inhibited HMGB1-mediated hyperpermeability and leukocyte migration in mice. In addition, treatment with MTU reduced CLP-induced release of HMGB1 and sepsis-related mortality and pulmonary injury. Our results indicate that MTUs could be candidate therapeutic agents for various severe vascular inflammatory diseases via the inhibition of the HMGB1 signaling pathway.

Inhibitory effects of polyozellin from Polyozellus multiplex on HMGB1-mediated septic responses

AIM AND OBJECTIVE

The ubiquitous nuclear protein, high-mobility group box 1 (HMGB1), is released by activated macrophages and human umbilical vein endothelial cells (HUVECs) and functions as a late mediator of experimental sepsis. Polyozellin, which has been reported to have a variety of biological activities including antioxidant and anticancer activity, is the major active compound found in edible mushroom (Polyozellus multiplex). In this study, we investigated the antiseptic effects and underlying mechanisms of polyozellin against HMGB1-mediated septic responses in HUVECs and mice.

METHODS

The anti-inflammatory activities of polyozellin were determined by measuring permeability, human neutrophil adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice.

RESULTS

According to the results, polyozellin effectively inhibited lipopolysaccharide (LPS)-induced release of HMGB1, and suppressed HMGB1-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. In addition, polyozellin suppressed the production of tumor necrosis factor-α and interleukin (IL)-6, and the activation of nuclear factor-κB and extracellular signal-regulated kinases 1/2 by HMGB1.

CONCLUSION

Collectively, these results indicate that P. multiplex containing polyozellin could be commercialized as functional food for preventing and treatment of various severe vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Novel insight into drug repositioning: Methylthiouracil as a case in point

Drug repositioning refers to the development of existing drugs for new indications. These drugs may have (I) failed to show efficacy in late stage clinical trials without safety issues; (II) stalled in the development for commercial reasons; (III) passed the point of patent expiry; or (IV) are being explored in new geographic markets. Over the past decade, pressure on the pharmaceutical industry caused by the 'innovation gap' owing to rising development costs and stagnant product output have become major reasons for the growing interest in drug repositioning. Companies that offer a variety of broad platforms for identifying new indications have emerged; some have been successful in building their own pipelines of candidates with reduced risks and timelines associated with further clinical development. The business models and platforms offered by these companies will be validated if they are able to generate positive proof-of-concept clinical data for their repositioned compounds. This review describes the strategy of biomarker-guided repositioning of chemotherapeutic drugs for inflammation therapy, considering the repositioning of methylthiouracil (MTU), an antithyroid drug, as a potential anti-inflammatory reagent.

Antiseptic effect of vicenin-2 and scolymoside from Cyclopia subternata (honeybush) in response to HMGB1 as a late sepsis mediator in vitro and in vivo

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain. In this study, we investigated the antiseptic effects and underlying mechanisms of vicenin-2 and scolymoside, which are 2 active compounds from C. subternata that act against high mobility group box 1 (HMGB1)-mediated septic responses in human umbilical vein endothelial cells (HUVECs) and mice. The antiseptic activities of vicenin-2 and scolymoside were determined by measuring permeability, neutrophil adhesion and migration, and activation of proinflammatory proteins in HMGB1-activated HUVECs and mice. According to the results, vicenin-2 and scolymoside effectively inhibited lipopolysaccharide-induced release of HMGB1, and suppressed HMGB1-mediated septic responses such as hyperpermeability, the adhesion and migration of leukocytes, and the expression of cell adhesion molecules. In addition, vicenin-2 and scolymoside suppressed the production of tumor necrosis factor-α and interleukin 6, and activation of nuclear factor-κB and extracellular regulated kinases 1/2 by HMGB1. Collectively, these results indicate that vicenin-2 and scolymoside could be a potential therapeutic agents for the treatment of various severe vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.

Tgfbi deficiency leads to a reduction in skeletal size and degradation of the bone matrix

Transforming growth factor-β-induced gene product-h3 (TGFBI/BIGH3) is an extracellular matrix protein expressed in a wide variety of tissues. TGFBI binds to type I, II, and IV collagens, as well as to biglycan and decorin and plays important roles in cell-to-cell, cell-to-collagen, and cell-to-matrix interactions. Furthermore, TGFBI is involved in cell growth and migration, tumorigenesis, wound healing, and apoptosis. To investigate whether TGFBI is involved in the maintenance of skeletal tissues, Tgfbi knockout mice were generated by crossing male and female Tgfbi heterozygous mice. Skeletal preparation showed that the skeletal size in Tgfbi knockout mice was smaller than in wild-type and heterozygous mice. However, chondrocytic cell alignment in the growth plates, bone mineral density, and bone forming rates were similar in Tgfbi knockout, wild-type, and heterozygous mice. Alterations in skeletal tissue arrangements in Tgfbi knockout mice were estimated from safranin O staining, trichrome staining, and immunohistochemistry for type II and X collagen, and matrix metalloproteinase 13 (MMP13). Cartilage matrix degradation was observed in the articular cartilage of Tgfbi knockout mice. Although the detection of type II collagen in the articular cartilage was lower in Tgfbi knockout mice than wild-type mice, the detection of MMP13 was markedly higher, indicating that Tgfbi deficiency is associated with the degradation of cartilage matrix. These results suggest that TGFBI plays an important role in maintaining skeletal tissues and the cartilage matrix in mice.

Anti-transforming growth factor β-induced protein antibody ameliorates vascular barrier dysfunction and improves survival in sepsis

AIM

Sepsis is a systemic inflammatory response syndrome resulting from a microbial infection. Transforming growth factor β-induced protein (TGFBIp) is an extracellular matrix protein expressed by human endothelial cells and platelets that induces sepsis through interaction with integrin αvβ5. The aim of this study was to investigate the role of TGFBIp in vascular permeability and the underlying mechanisms using TGFBIp-neutralizing antibody.

METHODS

Mice were subjected to caecal ligation and puncture (CLP) with or without neutralizing anti-TGFBIp antibody (300 μg kg(-1), intravenously). Wild-type or integrin β5-null mice received TGFBIp (0.1 mg kg(-1), intravenously) or were subjected to CLP. Human umbilical vein endothelial cells were exposed to lipopolysaccharide (100 ng mL(-1)) with or without neutralizing anti-TGFBIp antibody (50 μg mL(-1)).

RESULTS

Administration of neutralizing anti-TGFBIp antibody in mice attenuated CLP-induced secretion of TGFBIp, leucocyte migration and vascular permeability and reduced septic mortality. Injected TGFBIp did not enhance vascular barrier permeability or leucocyte migration in β5-null mice. Finally, neutralizing anti-TGFBIp antibody inhibited the specific interactions between TGFBIp and its receptor, integrin αvβ5.

CONCLUSION

Our findings demonstrate that treatment with a TGFBIp-neutralizing antibody can ameliorate the deleterious effects of sepsis.