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Objective: VEGF (vascular endothelial growth factor) plays a critical role in physiological and pathological angiogenesis. Endothelial 3D podosomes (3DPs) are a type of F-actin-rich membrane microdomain, predominantly found in endothelial tip cells controlled by VEGF signaling during sprouting angiogenesis, such as occurs in retinal vasculature development. The molecular mechanisms governing 3DP formation have not been completely elucidated. Approach and Results: By using in vitro cell models and in vivo mouse models, we study the role of TM (thrombomodulin) in VEGF-induced endothelial 3DPs. Here, we report that VEGF can induce the expression of TM via ROCK2 (Rho-associated coiled-coil kinase 2). Furthermore, ROCK2 can catalyze the phosphorylated activation of ezrin to promote the association of the cytoplasmic domain of TM with F-actin in 3DPs and thereby promote the formation of 3DPs. We used endothelial cells transfected with different TM mutants as models to verify the role of TM domains in 3DPs and angiogenic activity. TM expression in endothelial cells augments angiogenic activity, a response that is dependent on the interaction of the cytoplasmic tail of TM with ezrin, and the integrity of the lectin-like domain of TM. Thus, as compared with wild-type counterparts, mice lacking the lectin-like domain of TM exhibit reduced neovascularization of granulation tissues during cutaneous wound healing and less retinal neovascularization in a model of oxygen-induced retinopathy. Conclusions: VEGF-ROCK2-ezrin-TM-F-actin axis promotes the formation of the lipid raft membrane-associated complex configuration, 3DP, which plays a critical role in mediating tube formation and cell migration of endothelial cells in sprouting angiogenesis.

Background and aims Thrombomodulin (TM) is an endothelial cell membrane-bound anticoagulant protein expressed in normal arteries. After vascular injury, medial and neointimal smooth muscle cells (SMCs) exhibit large amounts of TM. The purpose of this study was to investigate the physiological significance of vascular SMC-bound TM. Methods The morphology, expression of phenotype markers and cell behaviors of cultured aortic SMCs after knockdown of TM were observed. Transgenic mice with SMC-specific TM deletion were generated, and carotid neointima formation was induced by carotid ligation. Results Cultured human aortic SMCs displayed a synthetic phenotype with a rhomboid-shaped morphology and expressed TM. TM knockdown induced a spindle-shaped change in morphology with an increased expression of contractile phenotype marker and decreased expression of synthetic phenotype marker. TM knockdown not only attenuated the proliferation of SMCs but also reduced tumor necrosis factor-α-induced nuclear factor-κB activation and interlukin-6 production. In a carotid artery ligation model, transgenic mice with SMC-specific TM deletion (SM22-cretg/TMflox/flox) had significantly less cellular proliferation in arterial walls compared with wild type mice (SM22-cretg/TM+/+). The neointima area and neointima/media area ratio were smaller in SM22-cretg/TMflox/flox mice at 4 weeks after ligation. Conclusions Our results indicate that vascular SMC-bound TM plays a role in changes of the SMC phenotype. It also influences SMC cell behavior and injury-induced neointima formation.

Deleterious hyper-inflammation resulting from macrophage activation may aggravate sepsis and lead to lethality. Tumor endothelial marker 1 (TEM1), a type I transmembrane glycoprotein containing six functional domains, has been implicated in cancer and chronic sterile inflammatory disorders. However, the role of TEM1 in acute sepsis remains to be determined. Herein we explored the functional significance of the TEM1 lectin-like domain (TEM1D1) in monocyte/macrophage activation and sepsis using TEM1D1-deleted (TEM1LeD/LeD) transgenic mice and recombinant TEM1D1 (rTEM1D1) protein. Under stimulation with lipopolysaccharides (LPS) or several other toll-like receptor agonists, TEM1LeD/LeD macrophages produced lower levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 than wild-type TEM1wt/wt macrophages. Compared with TEM1wt/wt macrophages, LPS-macrophage binding and intracellular mitogen-activated protein kinase (MAPK)/nuclear factor (NF)-κB activation were suppressed in TEM1LeD/LeD macrophages. In vivo, TEM1D1 deletion improved survival in LPS-challenged mice with reduction of circulating TNF-α and IL-6 and alleviation of lung injury and pulmonary leukocyte accumulation. In contrast, rTEM1D1 could bind to LPS and markedly suppress LPS-macrophage binding, MAPK/NF-κB signaling in macrophages and proinflammatory cytokine production. Treatment with rTEM1D1 improved survival and attenuated circulating TNF-α and IL-6, lung injury and pulmonary accumulation of leukocytes in LPS-challenged mice. These findings demonstrated differential roles for the TEM1 lectin-like domain in macrophages and soluble TEM1 lectin-like domain in sepsis. TEM1 in macrophages mediates LPS-induced inflammation via its lectin-like domain, whereas rTEM1D1 interferes with LPS-induced macrophage activation and sepsis.

Background Thrombomodulin (TM), an integral membrane protein, has long been known for its anticoagulant activity. Recent studies showed that TM displays multifaceted activities, including the involvement in cell adhesion and collective cell migration in vitro. However, whether TM contributes similarly to these biological processes in vivo remains elusive. Methods We adapted zebrafish, a prominent animal model for studying molecular/cellular activity, embryonic development, diseases mechanism and drug discovery, to examine how TM functions in modulating cell migration during germ layer formation, a normal and crucial physiological process involving massive cell movement in the very early stages of life. In addition, an in vivo assay was developed to examine the anti-hemostatic activity of TM in zebrafish larva. Results We found that zebrafish TM-b, a zebrafish TM-like protein, was expressed mainly in vasculatures and displayed anti-hemostatic activity. Knocking-down TM-b led to malformation of multiple organs, including vessels, heart, blood cells and neural tissues. Delayed epiboly and incoherent movement of yolk syncytial layer were also observed in early TM-b morphants. Whole mount immunostaining revealed the co-localization of TM-b with both actin and microtubules in epibolic blastomeres. Single-cell tracking revealed impeded migration of blastomeres during epiboly in TM-b-deficient embryos. Conclusion Our results showed that TM-b is crucial to the collective migration of blastomeres during germ layer formation. The structural and functional compatibility and conservation between zebrafish TM-b and mammalian TM support the properness of using zebrafish as an in vivo platform for studying the biological significance and medical use of TM. Electronic supplementary material The online version of this article (10.1186/s12929-019-0549-2) contains supplementary material, which is available to authorized users.

Figure S1. The alignment and identity of zTHBD primary sequence with those of zebrafish TM-a and TM-b. Figure S2. Efficiency of zTM-b MO. Figure S3. Schematic diagram of the predictive ETS-1 binding sites in TM promoter. Figure S4. The zTM-b morphants did not recover from the developmental anomalies as the embryogenesis proceeding to the later stages. Figure S5. In vitro activity assay for thrombomodulin. (PDF 1830 kb)

Plasminogen (Plg) and thrombomodulin (TM) are glycoproteins well known for fibrinolytic and anticoagulant functions, respectively. Both Plg and TM are essential for wound healing. However, their significance during the reparative process was separately demonstrated in previous studies. Here, we investigate the interaction between Plg and epithelial TM and its effect on wound healing. Characterization of the wound margin revealed that Plg and TM were simultaneously upregulated at the early stage of wound healing and the two molecules were bound together. In vitro, TM silencing or knockout in keratinocytes inhibited Plg activation. Plg treatment enhanced keratinocyte proliferation and migration, and these actions were abolished by TM antibody. Keratinocyte-expressed vascular endothelial growth factor (VEGF), which presented a dose-response relationship with Plg treatment, can be suppressed by TM silencing. Moreover, treatment with VEGF antibody inhibited Plg-enhanced keratinocyte proliferation and wound recovery. In vivo, TM antibody treatment and keratinocyte-specific TM knockout can impede Plg-enhanced wound healing in mice. In high-glucose environments, Plg-enhanced VEGF expression and wound healing were suppressed due at least in part to downregulation of keratinocyte-expressed TM. Taken together, our findings suggest that activation of Plg/TM signaling may hold therapeutic potential for chronic wounds in diabetic or non-diabetic individuals. KEY MESSAGES: Plg binds to TM in cutaneous wound healing. TM facilitates the activation of Plg to Plm in keratinocytes. Epithelial TM regulates Plg-enhanced wound healing through VEGF expression.

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CD14, a multiligand pattern-recognition receptor, is involved in the activation of many TLRs. Thrombomodulin (TM), a type I transmembrane glycoprotein, originally was identified as an anticoagulant factor that activates protein C. Previously, we showed that the recombinant TM lectin-like domain binds to LPS and inhibits LPS-induced inflammation, but the function of the recombinant epidermal growth factor–like domain plus serine/threonine-rich domain of TM (rTMD23) in LPS-induced inflammation remains unknown. In the current study, we found that rTMD23 markedly suppressed the activation of intracellular signaling pathways and the production of inflammatory cytokines induced by LPS. The anti-inflammatory activity of rTMD23 was independent of activated protein C. We also found that rTMD23 interacted with the soluble and membrane forms of CD14 and inhibited the CD14-mediated inflammatory response. Knockdown of CD14 in macrophages suppressed the production of inflammatory cytokines induced by LPS, and rTMD23 inhibited LPS-induced IL-6 production in CD14-knockdown macrophages. rTMD23 suppressed the binding of LPS to macrophages by blocking the association between monocytic membrane-bound TM and CD14. The administration of rTMD23 in mice, both pretreatment and posttreatment, significantly increased the survival rate and reduced the inflammatory response to LPS. Notably, the serine/threonine-rich domain is essential for the anti-inflammatory activity of rTMD23. To summarize, we show that rTMD23 suppresses the LPS-induced inflammatory response in mice by targeting CD14 and that the serine/threonine-rich domain is crucial for the inhibitory effect of rTMD23 on LPS-induced inflammation.

Stress-induced alteration in endothelial cells (ECs) integrity precedes the development of atherosclerosis. Previous studies showed that the soluble recombinant thrombomodulin (rTM) not only increases ECs proliferation but also exerts anti-apoptotic activity in ECs. However, the functional significance of soluble rTM on autophagy-related apoptosis in ECs is still undetermined. Implicating a cytoprotective role for rTM in persistent serum starvation (SS)-induced autophagy in cultured ECs, we found that treatment of rTM decreased the expression of SS-induced autophagy-related proteins, ATG5 and LC3, and the formation of autophagosomes through activation of AKT/mTOR pathway. In addition, treatment of rTM decreased SS-induced EC apoptosis, but this effect of rTM could not be recapitulated by co-treatment with a potent autophagy inducer, rapamycin and in ECs with ATG5 knockdown. In human atherosclerosis specimens, expression of autophagy markers, ATG13 and LC3, were more abundant in aortic intimal ECs with severe atherosclerosis than those without atherosclerosis. Moreover, compared to saline treatment group, administration of rTM reduced LC3 and ATG13 expression, intimal EC apoptosis, and atherosclerotic lesion severity in the aorta of apolipoprotein E deficient mice. In conclusion, treatment with rTM suppressed stress-induced autophagy overactivation in ECs, provided ECs protective effects, and decreased atherosclerosis in apolipoprotein E deficient mice.

Aims The recombinant epidermal growth factor-like domain plus the serine/threonine-rich domain of thrombomodulin (rTMD23) promotes angiogenesis and accelerates the generation of activated protein C (APC), which facilitates angiogenesis. The aim of this study was to elucidate the molecular mechanisms underlying the angiogenic activity of rTMD23. Methods and results We prepared rTMD23 and its mutants that did not possess the ability to promote APC generation and investigated their angiogenic activities in vitro and in vivo . rTMD23 mutants promoted proliferation, migration, and tube formation of human umbilical vein endothelial cells in vitro and induced neovascularization in vivo ; these effects were similar to those exerted by wild-type rTMD23. To investigate its interaction with rTMD23, Type I fibroblast growth factor receptor (FGFR1) was precipitated along with syndecan-4 by rTMD23-conjugated Sepharose in human umbilical vein endothelial cells and FGFR1-expressing human embryonic kidney 293 cells. Additionally, the kinetics of the interaction between rTMD23 and FGFR1 were analysed using surface plasmon resonance. rTMD23-induced FGFR1 activation and tube formation were inhibited by an FGFR1-specific tyrosine kinase inhibitor, PD173074, or by knockdown of FGFR1 using siRNA technology. We observed an improvement in rat hindlimb recovery in an ischaemic model following rTMD23 treatment, and this was associated with increased neovascularization and FGFR1 phosphorylation. Conclusion rTMD23 induced angiogenesis via FGFR1, a process that is independent of the APC pathway.

Background Thrombomodulin (TM) is an endothelial cell (EC) membrane-bound anticoagulant protein that has novel direct cellular effects. TM is shed from EC and becomes soluble form (sTM) in plasma. Higher sTM levels in healthy subjects are associated with lower cardiovascular risk, suggesting that sTM possesses a protective role. The purpose of the study was to evaluate the effect of sTM on vascular endothelium. Methods and results Apoptosis of cultured ECs was induced via serum starvation. EC-bound TM was released into the medium after serum starvation. The medium conditioned by serum-starved EC decreased apoptosis in another set of cultured EC. Direct treatment with sTM reduced EC apoptosis and decreased pro-apoptotic protein expression. TM knockdown in EC exacerbated the rate of serum starvation-induced apoptosis. Treatment of sTM activated the phosphatidylinositol 3-kinase (PI3 kinase)–protein kinase B/Akt survival pathway and suppressed the death pathway, c-Jun N-terminal kinase. We found that sTM also increased growth and reduced apoptosis of endothelial progenitor cells. Conclusions EC-bound TM is released during stress-induced EC damage and becomes sTM, a paracrine factor that exerts anti-apoptotic activity. Our data indicate that sTM is not only an endothelial injury biomarker but also has cytoprotective effects on vascular endothelium.

Tumor endothelial marker 1 (TEM1), also known as endosialin or CD248, is a type I transmembrane glycoprotein containing a C-type lectin-like domain. It is highly expressed in pericytes and fibroblasts. Dermal fibroblasts play a pivotal role during cutaneous wound healing, especially in the proliferative phase. However, the physiological function of TEM1 in wound healing is still undetermined. During the process of wound healing, the expression of both TEM1 and platelet-derived growth factor (PDGF) receptor α was highly upregulated in myofibroblasts. In vivo, fibroblast activation and collagen deposition in granulation tissues were attenuated, and wound healing was retarded in TEM1-deleted mice. In vitro, the migration, adhesion, and proliferation of NIH3T3 cells were suppressed following TEM1 knockdown by short hairpin RNA. In PDGF-BB-treated NIH3T3 cells, the downstream signal and mitogenic, and chemoattractive effects were inhibited by TEM1 knockdown. In addition, TEM1 and PDGF receptor α were colocalized in subcellular organelles in fibroblasts, and the association of TEM1 and PDGF receptor α was demonstrated by coimmunoprecipitation. In summary, these findings suggested that TEM1, in combination with PDGF receptor α, plays a critical role in wound healing by enhancing the mitogenic and chemoattractive effects of PDGF-BB and collagen deposition in myofibroblasts.

To investigate whether recombinant thrombomodulin containing all the extracellular domains (rTMD123) has therapeutic potential against aneurysm development.The pathogenesis of abdominal aortic aneurysm (AAA) is characterized by chronic inflammation and proteolytic degradation of extracellular matrix. Thrombomodulin, a transmembrane glycoprotein, exerts anti-inflammatory activities such as inhibition of cytokine production and sequestration of proinflammatory high-mobility group box 1 (HMGB1) to prevent it from engaging the receptor for advanced glycation end product (RAGE) that may sustain inflammation and tissue damage.The in vivo effects of treatment and posttreatment with rTMD123 on aortic dilatation were measured using the CaCl2-induced AAA model in mice.Characterization of the CaCl2-induced model revealed that HMGB1 and RAGE, both localized mainly to macrophages, were persistently upregulated during a 28-day period of AAA development. In vitro, rTMD123-HMGB1 interaction prevented HMGB1 binding to macrophages, thereby prohibiting activation of HMGB1-RAGE signaling in macrophages. In vivo, short-term treatment with rTMD123 upon AAA induction suppressed the levels of proinflammatory cytokines, HMGB1, and RAGE in the aortic tissue; reduced the infiltrating macrophage number; and finally attenuated matrix metalloproteinase production, extracellular matrix destruction, and AAA formation without disturbing vascular calcification. Consistently, posttreatment with rTMD123 seven days after AAA induction alleviated vascular inflammation and retarded AAA progression.These data suggest that rTMD123 confers protection against AAA development. The mechanism of action may be associated with reduction of proinflammatory mediators, blockade of macrophage recruitment, and suppression of HMGB1-RAGE signaling involved in aneurysm formation and downstream macrophage activation.

Chronic inflammatory processes have been increasingly shown to be involved in the pathogenesis of diabetes and diabetic nephropathy. Recently, we demonstrated that a lectin-like domain of thrombomodulin (THBD), which is known as THBD domain 1 (THBDD1) and which acts independently of protein C activation, neutralised an inflammatory response in a mouse model of sepsis. Here, therapeutic effects of gene therapy with adeno-associated virus (AAV)-carried THBDD1 (AAV-THBDD1) were tested in a mouse model of type 2 diabetic nephropathy.To assess the therapeutic potential of THBDD1 and the mechanisms involved, we delivered AAV-THBDD1 (10(11) genome copies) into db/db mice and tested the effects of recombinant THBDD1 on conditionally immortalised podocytes.A single dose of AAV-THBDD1 improved albuminuria, renal interstitial inflammation and glomerular sclerosis, as well as renal function in db/db mice. These effects were closely associated with: (1) inhibited activation of the nuclear factor κB (NF-κB) pathway and the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome; (2) promotion of nuclear factor (erythroid-derived 2)-like 2 (NRF2) nuclear translocation; and (3) suppression of mitochondria-derived apoptosis in the kidney of treated mice.AAV-THBDD1 gene therapy resulted in improvements in a model of diabetic nephropathy by suppressing the NF-κB-NLRP3 inflammasome-mediated inflammatory process, enhancing the NRF2 antioxidant pathway and inhibiting apoptosis in the kidney.

Objective— The N-terminal lectin-like domain (domain 1 [D1]) of thrombomodulin (TM) is known to have an anti-inflammatory function. We previously showed that recombinant TM domain 1 (rTMD1) interacts with a carbohydrate molecule, Lewis Y (Le y ), which is found to be expressed on adhesion molecules and involved in cell adhesion. Here, we tested the effect of rTMD1/Le y interaction on leukocyte recruitment in inflammation. Approach and Results— The expression of Le y on the surface of human umbilical vein endothelial cells was increased by tumor necrosis factor-α stimulation. Direct binding of rTMD1 to Le y on the cell surface was observed. rTMD1 inhibited Le y -mediated leukocyte adhesion on the Le y -immobilized flow chamber and activated endothelium under a shear flow. The following leukocyte transmigration to endothelium was also reduced by rTMD1 through binding Le y . In vivo, treatment of rTMD1 reduced leukocyte recruitment to the inflammatory sites in carotid ligation injury and thioglycollate-induced peritonitis. rTMD1 administration in apolipoprotein E–deficient mice effectively suppressed atherosclerotic plaque formation and macrophage infiltration in atherosclerotic lesions. Increased Le y expression, as well as administered rTMD1, was observed in inflamed vessels. Conclusions— rTMD1 suppresses vascular inflammation by inhibiting leukocyte recruitment to endothelium through attenuating Le y -mediated adhesion and further protects against atherosclerosis progression. The present study provides a mechanism showing that rTMD1 can inhibit inflammation by binding to its carbohydrate ligand Le y .

Urokinase-type plasminogen activator (uPA) activates plasminogen (Plg) through a major pericellular proteolytic system involved in cell migration and angiogenesis; however, the Plg receptor that participates in uPA-mediated Plg activation has not yet been identified. In this study, we demonstrated that thrombomodulin (TM), a type I transmembrane glycoprotein, is a novel Plg receptor that plays a role in pericellular proteolysis and cell migration. Plg activation at the cell surface and the extent of its cell migration- and invasion-promoting effect are cellular TM expression dependent. Direct binding of Plg and the recombinant TM extracellular domain, with a KD of 0.1-0.3 μM, was determined through surface plasmon resonance analysis. Colocalization of TM, Plg, and the uPA receptor within plasma membrane lipid rafts, at the leading edge of migrating endothelial cells, was demonstrated and was also shown to overlap with areas of major pericellular proteolysis. Moreover, the roles of TM and Plg in neoangiogenesis were demonstrated in vivo through the skin wound-healing model. In conclusion, we propose that TM is a novel Plg receptor that regulates uPA/uPA receptor-mediated Plg activation and pericellular proteolysis within lipid rafts at the leading edge of migrating cells during angiogenesis.

Objective This study examines the effect of Dextromethorphan (d-3-methoxy-17-methylmorphinan; DXM), a commonly used cough-suppressing drug, on the expression of VCAM-1 and ICAM-1 in human umbilical vein endothelial cells (HUVECs) stimulated with lipopolysaccharide (LPS). Methods The effect of DXM on expression of cell adhesion molecules induced by LPS was evaluated by monocyte bindings in vitro and ex vivo and transmigration assays. The signaling pathways involved in the inflammation inhibitory effect of DXM were analyzed by Western blot and immunofluorescent stain. Results Pretreatment of HUVECs with DXM inhibited LPS-induced adhesion of THP-1 cells in vitro and ex vivo, and reduced transendothelial migration of these cells. Furthermore, treatment of HUVECs with DXM can significantly decrease LPS-induced expression of ICAM-1 and VCAM-1. DXM abrogated LPS-induced phosphorylation of ERK and Akt. The translocation of early growth response gene-1 (Egr-1), a downstream transcription factor involved in the mitogen-activated kinase (MEK)-ERK signaling pathway, was suppressed by DXM treatment. Furthermore, DXM inhibited LPS-induced IκBα degradation and nuclear translocation of p65. Conclusions Dextromethorphan inhibits the adhesive capacity of HUVECs by reducing the LPS-induced ICAM-1 and VCAM-1 expression via the suppression of the ERK, Akt, and NF-κB signaling pathways. Thus, DXM is a potential anti-inflammatory therapeutic that may modulate atherogenesis.

Background and aims Thrombomodulin (TM), through its lectin-like domain (TMD1), sequesters proinflammatory high-mobility group box 1 (HMGB1) to prevent it from engaging the receptor for advanced glycation end product (RAGE) that sustains inflammation and tissue damage. Our previous study demonstrated that short-term treatment with recombinant TM containing all the extracellular domains (i.e., rTMD123) inhibits HMGB1-RAGE signaling and confers protection against CaCl 2 -induced AAA formation. In this study, we attempted to further optimize TM domains, as a potential therapeutic agent for AAA, using the recombinant adeno-associated virus (AAV) vector. Methods The therapeutic effects of recombinant TMD1 (rTMD1) and recombinant AAV vectors carrying the lectin-like domain of TM (rAAV-TMD1) were evaluated in the CaCl 2 -induced AAA model and angiotensin II-infused AAA model, respectively. Results In the CaCl 2 -induced model, treatment with rTMD1 suppressed the tissue levels of HMGB1 and RAGE, macrophage accumulation, elastin destruction and AAA formation, and the effects were comparable to a mole-equivalent dosage of rTMD123. In the angiotensin II-infused model, a single intravenous injection of rAAV-TMD1 (10 11 genome copies), which resulted in a persistently high serum level of TMD1 for at least 12 weeks, effectively attenuated AAA formation with suppression of HMGB1 and RAGE levels and inhibition of proinflammatory cytokine production, macrophage accumulation, matrix metalloproteinase activities and oxidative stress in the aortic wall. Conclusions These findings corroborate the therapeutic potential of the TM lectin-like domain in AAA. The attenuation of angiotensin II-infused AAA by one-time delivery of rAAV-TMD1 provides a proof-of-concept validation of its application as potential gene therapy for aneurysm development.

Toll-like receptor (TLR) family plays a key role in innate immunity and various inflammatory responses. TLR4, one of the well-characterized pattern-recognition receptors, can be activated by endogenous damage-associated molecular pattern molecules such as high mobility group box 1 (HMGB1) to sustain sterile inflammation. Evidence suggested that blockade of TLR4 signaling may confer protection against abdominal aortic aneurysm (AAA). Herein we aimed to obtain further insight into the mechanism by which TLR4 might promote aneurysm formation. Characterization of the CaCl2-induced AAA model in mice revealed that upregulation of TLR4 expression, localized predominantly to vascular smooth muscle cells (VSMCs), was followed by a late decline during a 28-day period of AAA development. In vitro, TLR4 expression was increased in VSMCs treated with HMGB1. Knockdown of TLR4 by siRNA attenuated HMGB1-enhanced production of proinflammatory cytokines, specifically interleukin-6 and monocyte chemoattractant protein-1 (MCP-1), and matrix-degrading matrix metalloproteinase (MMP)-2 from VSMCs. In vivo, two different strains of TLR4-deficient (C57BL/10ScNJ and C3H/HeJ) mice were resistant to CaCl2-induced AAA formation compared to their respective controls (C57BL/10ScSnJ and C3H/HeN). Knockout of TLR4 reduced interleukin-6 and MCP-1 levels and HMGB1 expression, attenuated macrophage accumulation, and eventually suppressed MMP production, elastin destruction and VSMC loss. Finally, human AAA exhibited higher TLR4 expression that was localized to VSMCs. These data suggest that TLR4 signaling contributes to AAA formation by promoting a proinflammatory status of VSMCs and by inducing proteinase release from VSMCs during aneurysm initiation and development.

Adhesive interactions between cells are needed to maintain tissue architecture during development, tissue renewal and wound healing. Thrombomodulin (TM) is an integral membrane protein that participates in cell-cell adhesion through its extracellular lectin-like domain. However, the molecular basis of TM-mediated cell-cell adhesion is poorly understood. Here, we demonstrate that TM is linked to the actin cytoskeleton via ezrin. In vitro binding assays showed that the TM cytoplasmic domain bound directly to the N-terminal domain of ezrin. Mutational analysis of the TM cytoplasmic domain identified (522)RKK(524) as important ezrin-binding residues. In epidermal epithelial A431 cells, TM colocalized with ezrin and actin filaments at cell-cell contacts. Knockdown of endogenous TM expression by RNA interference induced morphological changes and accelerated cell migration in A431 cells. Moreover, epidermal growth factor, upstream of ezrin activation, stimulated the interaction between ezrin and TM. In skin wound healing of mice, TM and ezrin were highly expressed in neoepidermis, implying that both proteins are key molecules in reepithelialization that requires collective cell migration of epithelial cells. Finally, exogenous expression of TM in TM-deficient melanoma A2058 cells promoted collective cell migration. In summary, TM, which associates with ezrin and actin filaments, maintains epithelial morphology and promotes collective cell migration.

The activation of coagulation factors V and X by Russell's viper venom (RVV) has been implicated in the development of consumptive coagulopathies in severely envenomed patients. However, factor Va is prone to inactivation by activated protein C (APC), an important serine protease that negatively regulates blood coagulation. It is therefore hypothesized that APC may be down-regulated by some of the venom components. In this study, we managed to isolate a potent Kunitz-type APC inhibitor, named DrKIn-I. Using chromogenic substrate, DrKIn-I dose-dependently inhibited the activity of APC. Heparin potentiated the inhibition and reduced the IC(50) of DrKIn-I by 25-fold. DrKIn-I, together with heparin, also protected factor Va from APC-mediated inactivation. Using surface plasmon resonance, DrKIn-I exhibited fast binding kinetics with APC (association rate constant = 1.7 × 10(7) M(-1) s(-1)). Direct binding assays and kinetic studies revealed that this inhibition (K(i) = 53 pM) is due to the tight binding interactions of DrKIn-I with both heparin and APC. DrKIn-I also effectively reversed the anticoagulant activity of APC and completely restored the thrombin generation in APC-containing plasma. Furthermore, although the injection of either DrKIn-I or RVV-X (the venom factor X-activator) into ICR mice did not significantly deplete the plasma fibrinogen concentration, co-administration of DrKIn-I with RVV-X resulted in complete fibrinogen consumption and the deposition of fibrin thrombi in the glomerular capillaries. Our results provide new insights into the pathogenesis of RVV-induced coagulopathies and indicate that DrKIn-I is a novel APC inhibitor that is associated with potentially fatal thrombotic complications in Russell's viper envenomation.

Lewis Y Ag (LeY) is a cell-surface tetrasaccharide that participates in angiogenesis. Recently, we demonstrated that LeY is a specific ligand of the recombinant lectin-like domain of thrombomodulin (TM). However, the biologic function of interaction between LeY and TM in endothelial cells has never been investigated. Therefore, the role of LeY in tube formation and the role of the recombinant lectin-like domain of TM—TM domain 1 (rTMD1)—in antiangiogenesis were investigated. The recombinant TM ectodomain exhibited lower angiogenic activity than did the recombinant TM domains 2 and 3. rTMD1 interacted with soluble LeY and membrane-bound LeY and inhibited soluble LeY-mediated chemotaxis of endothelial cells. LeY was highly expressed on membrane ruffles and protrusions during tube formation on Matrigel. Blockade of LeY with rTMD1 or Ab against LeY inhibited endothelial tube formation in vitro. Epidermal growth factor (EGF) receptor in HUVECs was LeY modified. rTMD1 inhibited EGF receptor signaling, chemotaxis, and tube formation in vitro, and EGF-mediated angiogenesis and tumor angiogenesis in vivo. We concluded that LeY is involved in vascular endothelial tube formation and rTMD1 inhibits angiogenesis via interaction with LeY. Administration of rTMD1 or recombinant adeno-associated virus vector carrying TMD1 could be a promising antiangiogenesis strategy.

Objective— We examined the effect of thrombomodulin (TM) domains 2 and 3 (TMD23) on human early endothelial progenitor cells (EPCs). Methods and Results— TM was expressed and released by human EPCs cultured from peripheral blood mononuclear cells (PBMCs). Addition of TMD23 (100 ng/mL) to the cultured PBMCs increased the colony-forming units, chemotactic motility, matrix metalloproteinase activity, and interleukin-8 secretion but decreased tumor necrosis factor-α (TNF-α) release. Analysis of the signal pathway showed that TMD23 activated Akt. Inhibition of phosphatidylinositol-3 kinase–Akt blocked the effects of TMD23 on chemotactic motility, matrix metalloproteinase-9, interleukin-8, and TNF-α. In hindlimb ischemia mice, laser Doppler perfusion imaging of the ischemic limb during the 21 days after arterial ligation showed that the perfusion recovered best with intraperitoneal infusion of TMD23 plus local injection of early EPCs, followed by either infusion of TMD23 or injection of the cells. Animals without either treatment had the worst results. Animals treated with TMD23 also had lower circulating and tissue levels of TNF-α. Conclusion— TM is expressed and released by human circulating EPCs. Exogenous TMD23 enhances the angiogenic potential of early EPCs in vitro through activation of phosphatidylinositol-3 kinase-Akt pathway. Coadministration of TMD23 plus early EPCs augments therapeutic angiogenesis of the EPCs in ischemic tissues.

Aims Macrophage-related oxidative stress plays an important role in the inflammatory process in atherosclerosis. Recently, dextromethorphan (DXM), a common cough-suppressing ingredient with a high safety profile, was found to inhibit the activation of microglia, the resident macrophage in the nervous system. We investigated whether DXM could reduce macrophage production of cytokines and superoxide and the resultant influence on atherosclerosis formation in mice. Methods and results We used in vitro and in vivo studies to evaluate the DXM inhibitory effect on oxidative stress. Dextromethorphan pretreatment significantly suppressed the production of tumour necrosis factor-α, monocyte chemoattractant protein-1, interleukin-6, interleukin-10, and superoxide in macrophage cell culture after stimulation. Indeed, DXM reduced macrophage nicotinamide adenine dinucleotide phosphate oxidase activity by decreasing membrane translocation of p47phox and p67phox through the inhibition of protein kinase C and extracellular signal-regulated kinase activation. The anti-atherosclerosis effect of DXM was tested using two animal models, apolipoprotein E (apoE)-deficient mice and a mouse carotid ligation model. Dextromethorphan treatment (10–40 mg/kg/day) for 10 weeks in apoE-deficient mice significantly reduced superoxide production in their polymorphonuclear leukocytes and aortas. It significantly decreased the severity of aortic atherosclerosis in the apoE-deficient mice and decreased carotid neointima formation after ligation in C57BL/6 mice. Conclusion Our data show that DXM, with its novel effect in reducing oxidative stress, significantly reduces atherosclerosis and neointima formation in mice.

Thrombomodulin (TM) is a membrane-bound glycoprotein receptor r thrombin in the protein C activation pathway. Since its discovery in the 1980s as an anticoagulant protein, recent data suggest that TM plays an important role in modulating cellular proliferation, adhesion and inflammation. A soluble TM fragment has been produced with recombinant DNA technology that can bind thrombin and activate protein C. Soluble TM has received much attention because of its potential clinical applications. This article will examine recent advances in the understanding of TM's novel physiological function and review the molecular mechanisms of TM's anti-inflammatory effect. This review will also summarize TM data generated from animal studies and clinical trials to date and will focus on the role of TM in treating thrombotic, atherosclerotic and other inflammation-related diseases. These emerging data show that soluble TM is a promising agent that may provide potential therapies to modulate the pathophysiological process of atherothrombotic and other inflammatory diseases in the near future.

Aims Thrombomodulin (TM), a potent anticoagulant, is not detected in quiescent vascular smooth muscle cells (VSMCs). In diseased vessels, VSMC expresses TM, but the mechanisms are unclear. This study examined molecular mechanisms for TM expression in VSMCs. Methods and results Platelet-derived growth factor-BB (PDGF-BB) induced TM expression in cultured human aortic VSMCs. PDGF-induced TM is functional in activating protein C. TM induction was eliminated by inhibitors of Src kinase, phosphatidylinositol 3-kinase (PI3-kinase), and mammalian target of rapamycin (mTOR) and by expressing dominant-negative Akt while expressing active Akt-stimulated TM expression. PDGF-BB activated the TM promoter, and the deletion of a sequence segment −394/−255 drastically reduced TM promoter activity. Transcription factor E26 transformation-specific sequence-1 (Ets-1) was upregulated by PDGF-BB in a PI3-kinase- and mTOR-dependent manner. RNA interference of Ets-1 inhibited PDGF induction of TM, and overexpressing Ets-1 increased TM expression. Chromatin immunoprecipitation and electrophoretic mobility shift assay detected increased Ets-1 binding to the TM promoter after PDGF treatment. Following carotid artery ligation of C57/BL6 mice, PDGF-BB and TM were co-expressed in the media and neointima. Conclusion In VSMCs, PDGF-BB stimulates TM expression that is mainly mediated by Ets-1 via the Src kinase/PI3-kinase/Akt/mTOR signalling pathway. Furthermore, PDGF-BB may regulate TM expression in VSMCs during vascular remodelling.

A cDNA encoding for zebrafish gamma-glutamyl hydrolase (gammaGH) was cloned and inserted into a pET43.1a vector via SmaI and EcoRI sites and expressed in Rosetta (DE3) cells as a Nus-His-tag fusion enzyme (NH-zgammaGH). After induction with isopropyl thiogalactoside, the enzyme was purified with a Ni-Sepharose column, and approximately 8 mg of pure enzyme was obtained per liter of culture. The primary sequence of the recombinant zgammaGH was similar to mammalian gammaGH. Thrombin digestion of this NH-zgammaGH fusion protein resulted in zgammaGH with approximately 2-fold higher catalytic activity compared with the NH-zgammaGH fusion enzyme. This recombinant zgammaGH is active and exhibits comparable endopeptidase activity with folate substrate and antifolate drug methotrexate. Use of this recombinant zgammaGH significantly increased efficiency in folylpolyglutamate hydrolysis for folate analysis compared with current protocols.

Thrombomodulin (TM), a widely expressing glycoprotein originally identified in vascular endothelium, is an important cofactor in the protein C anticoagulant system. TM appears to exhibit anti-inflammatory ability through both protein C–dependent and –independent pathways. We presently have demonstrated that recombinant N-terminal lectinlike domain of TM (rTMD1) functions as a protective agent against sepsis caused by Gram-negative bacterial infections. rTMD1 caused agglutination of Escherichia coli and Klebsiella pneumoniae and enhanced the macrophage phagocytosis of these Gram-negative bacteria. Moreover, rTMD1 bound to the Klebsiella pneumoniae and lipopolysaccharide (LPS) by specifically interacting with Lewis Y antigen. rTMD1 inhibited LPS-induced inflammatory mediator production via interference with CD14 and LPS binding. Furthermore, rTMD1 modulated LPS-induced mitogen-activated protein kinase and nuclear factor-κB signaling pathway activations and inducible nitric oxide synthase expression in macrophages. Administration of rTMD1 protected the host by suppressing inflammatory responses induced by LPS and Gram-negative bacteria, and enhanced LPS and bacterial clearance in sepsis. Thus, rTMD1 can be used to defend against bacterial infection and inhibit LPS-induced inflammatory responses, suggesting that rTMD1 may be valuable in the treatment of severe inflammation in sepsis, especially in Gram-negative bacterial infections.

Summary. Background: Dextromethorphan (DM) is reported to reduce the inflammation-mediated degeneration of dopaminergic neurons. Objective: The goal of this study was to test if DM can improve the endothelial dysfunction and inflammatory markers in heavy smokers. Patients and methods: Forty habitual smoking healthy male volunteers (mean age, 31.5 ± 1.4 years) were randomly given either DM (120 mg day−1) or a placebo for 6 months. We determined endothelial function using the brachial artery diameter changes in flow-mediated dilatation (FMD) and measured their inflammatory and oxidative markers. A sex-and-age matched non-smoking group (n = 20) was compared as normal parameters. Results: Habitual smokers showed impaired baseline endothelial function in FMD (smoking vs. non-smoking: 6.3 ± 1.8 vs. 10.2 ± 2.3% respectively, P

Thrombomodulin (TM) is an anticoagulant glycoprotein highly expressed on endothelial cell surfaces. Increased levels of soluble TM in circulation have been widely accepted as an indicator of endothelial damage or dysfunction. Previous studies indicated that various proinflammatory factors stimulate TM shedding in various cell types such as smooth muscle cells and epithelial cells. Lysophosphatidic acid (LPA) is a bioactive lipid mediator present in biological fluids during endothelial damage or injury. In the present study, we first observed that LPA triggered TM shedding in human umbilical vein endothelial cells (HUVECs). By Cyflow analysis, we showed that the LPA-induced accessibility of antibodies to the endothelial growth factor (EGF)-like domain of TM is independent of matrix metalloproteinases (MMPs), while LPA-induced TM lectin-like domain shedding is MMP-dependent. Furthermore, a stable cell line expressing TM without its lectin-like domain exhibited a higher cell proliferation rate than a stable cell line expressing full-length TM. These results imply that LPA induces TM lectin-like domain shedding, which might contribute to the exposure of its EGF-like domain for EGF receptor (EGFR) binding, thereby stimulating subsequent cell proliferation. Based on our findings, we propose a novel mechanism for the exposure of TM EGF-like domain, which possibly mediates LPA-induced EGFR transactivation.

Angiogenesis plays a primary role in tumor growth and metastasis. Angiostatin, a proteolytic fragment containing the first four kringle domains of human plasminogen, can inhibit angiogenesis. The anti-angiogenic activities of kringle 1-5 (K(1-5)) and kringle 5 fragments of plasminogen are greater than angiostatin in inhibiting angiogenesis and angiogenesis-dependent tumor growth. To further optimize kringle fragment anti-angiogenic activities, mutations were created at the potential glycosylation sites Asn-289 and Thr-346 and the Lys binding site, Leu-532, at kringle 5, including K(1-5)N289A (replacing Asn by Ala at residue 289), K(1-5)T346A, K(1-5)L532R, K(1-5)N289A/T346A, K(1-5)T346A/L532R, K(1-5)N289A/L532R, and K(1-5)N289A/T346A/L532R. Wild-type and mutant K(1-5) proteins were expressed successfully by the Pichia pastoris expression system. Native K(1-5) from proteolytic cleavage and wild-type K(1-5) have similar activity in inhibiting basic fibroblast growth factor-induced endothelial cell proliferation. Among these mutated proteins, K(1-5)N289A/T346A/L532R exhibited the greatest effect in inhibiting endothelial cell proliferation and in inducing endothelial cell apoptosis. Integrin alpha(v)beta(3)-mediated adhesion of K(1-5)N289A/T346A/L532R to endothelial cells was more greatly enhanced when compared to wild type K(1-5). Furthermore, K(1-5)N289A/T346A/L532R was most potent in inhibiting basic fibroblast growth factor-induced angiogenesis in Matrigel assay in vivo. Angiogenesis-dependent tumor growth was inhibited by systemically injected K(1-5)N289A/T346A/L532R into mice. These results demonstrate that alteration of glycosylation and Lys binding properties could increase the anti-angiogenic action of K(1-5), possibly via enhanced interaction with integrin alpha(v)beta(3) in endothelial cells.

// Yun-Yan Hsu 1 , Guey-Yueh Shi 1, 2 , Kuan-Chieh Wang 1 , Chih-Yuan Ma 1 , Tsung-Lin Cheng 3, 4 , Hua-Lin Wu 1, 2 1 Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan 2 Cardiovascular Research Center, College of Medicine, National Cheng Kung University, Tainan, Taiwan 3 Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan 4 Orthopaedic Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan Correspondence to: Hua-Lin Wu, email: halnwu@mail.ncku.edu.tw Keywords: endothelial cells, VEGF, thrombomodulin, fibronectin, angiogenesis Received: December 10, 2015 Accepted: August 27, 2016 Published: September 02, 2016 ABSTRACT Angiogenesis promotes tumor growth and metastasis. Cell adhesion molecules interact with the extracellular matrix (ECM) and increase cell adhesion and migration during angiogenesis. Thrombomodulin (TM) is a cell surface transmembrane glycoprotein expressed in endothelial cells. However, the function and significance of TM in cell-matrix interactions and angiogenesis remain unclear. Here, we first demonstrated that recombinant lectin-like domain of TM interacts with an ECM protein, fibronectin, and identified the N-terminal 70-kDa domain of fibronectin as the TM-binding site. Exogenous expression of TM in TM-deficient A2058 melanoma cells enhanced cell adhesion and migration on fibronectin and invasion on Matrigel. In addition, TM increased focal adhesion kinase (FAK) phosphorylation and matrix metalloproteinase-9 production. In mice bearing subcutaneous B16F10 melanoma tumors, immunofluorescence analysis indicated that TM was highly expressed and co-localized with fibronectin on the tumor vasculature. The interaction between TM and fibronectin in tumor blood vessels was also validated by the proximity ligation assay. In human umbilical vein endothelial cells, up-regulation of TM by vascular endothelial growth factor (VEGF), a tumor angiogenic factor, promoted cell adhesion and tube formation, whereas TM knockdown by RNA interference attenuated VEGF-induced cell adhesion and tube formation. In summary, TM promotes angiogenesis by enhancing cell adhesion, migration, and FAK activation through interaction with fibronectin. TM may represent a novel target for inhibiting tumor angiogenesis.

Introduction: Thrombomodulin (TM), a glycoprotein predominantly expressed in endothelial cells, has been well known for its anti-coagulant and anti-inflammatory properties. Paradoxically, we recently found a promoting role of monocytic membrane-bound TM in experimental sepsis. Hypothesis: We assessed the hypothesis that membrane-bound TM may participate in vascular inflammation and the development of abdominal aortic aneurysm (AAA). Methods and Results: Characterization of the CaCl 2 -induced AAA in mice revealed that TM expression was mainly localized in vascular smooth muscle cells (VSMCs) and infiltrating macrophages. To investigate the function of membrane-bound TM in vivo, transgenic mice with myeloid- (LysMcre/TM flox/flox ) and VSMC-specific (SM22-cre tg /TM flox/flox ) TM ablation and their wild type counterparts were generated. In the CaCl 2 -induced AAA model, myeloid TM-deficient mice (n=12) but not VSMC TM-deficient mice (n=8), when compared with their wild-type respective controls (TM flox/flox , SM22-cre tg /TM +/+ ), showed attenuated accumulation of macrophages, reduced production of proinflammatory cytokines and suppressed levels of matrix metalloproteinase-9, thereby preventing progressive aortic dilatation. In vitro TM-deficient macrophages had reduced proinflammatory mediator production, macrophage-endothelial cell adhesion and intracellular oxidative stress (e.g., reactive oxygen species [ROS]) versus TM wild-type macrophages. In addition, deficiency of TM in hyperlipidemic mice (ApoE -/- /LysMcre/TM flox/flox , n=9) conferred protection against angiotensin II-infused AAA, compatible with dramatically diminished aortic ROS production and matrix metalloproteinase activities. Finally, human AAA samples (n=6) showed that TM signals were predominantly localized to infiltrating macrophages, implicating the potential involvement of monocytic membrane-bound TM in human diseases. Conclusion: Membrane-bound TM in macrophages plays a critical role in the development of AAA by enhancing macrophage-endothelial cell adhesion, proinflammatory mediator elaboration and intracellular ROS production.

Angiostatin and other plasminogen derivatives exhibit antitumor activities directly or indirectly, have demonstrated promising anticancer effects in preclinical studies, but have mostly failed in clinical trials partly due to their short serum half-lives. Our previous studies demonstrated that recombinant human plasminogen kringle 1-5 (K1-5) has superior antitumor activity compared with angiostatin. In addition, optimization of recombinant K1-5 with three amino acid substitutions enhances its antitumor effect. The current study was thus undertaken to evaluate prolonged expression of optimized K1-5 as cancer gene therapy. The recombinant adeno-associated virus (AAV) vector was used to express a secreted form of the optimized K1-5 (AAV-sK15tm) to improve its pharmacokinetic profile, which was considered to be the hurdle in angiostatin treatment of cancer. We successfully generated high-titer recombinant AAV vectors and observed sustained transgene expression for 567 days after a single injection of virus. The treated animals did not display any visible signs of abnormalities and showed normal serum biochemistry. The therapeutic potential of this treatment modality was demonstrated by both a strong inhibition of lung metastasis in the mouse B16F10 melanoma model and significant growth retardation of Lewis lung carcinoma xenografts in C57BL/6N mice as well as human A2058 melanoma xenografts in NOD/SCID (nonobese diabetic/severe combined immunodeficient) mice. Taken together, our results suggested that AAV-sK15tm produced long-term suppressive effects on cancer growth in vivo and should warrant serious consideration for clinical development.

Aberrant glycosylation changes normal cellular functions and represents a specific hallmark of cancer. Lewisy (Ley) carbohydrate upregulation has been reported in a variety of cancers, including or...

Objective— Thrombomodulin (TM), a glycoprotein constitutively expressed in the endothelium, is well known for its anticoagulant and anti-inflammatory properties. Paradoxically, we recently found that monocytic membrane-bound TM (ie, endogenous TM expression in monocytes) triggers lipopolysaccharide- and gram-negative bacteria–induced inflammatory responses. However, the significance of membrane-bound TM in chronic sterile vascular inflammation and the development of abdominal aortic aneurysm (AAA) remains undetermined. Approach and Results— Implicating a potential role for membrane-bound TM in AAA, we found that TM signals were predominantly localized to macrophages and vascular smooth muscle cells in human aneurysm specimens. Characterization of the CaCl 2 -induced AAA in mice revealed that during aneurysm development, TM expression was mainly localized in infiltrating macrophages and vascular smooth muscle cells. To investigate the function of membrane-bound TM in vivo, transgenic mice with myeloid- (LysMcre/TM flox/flox ) and vascular smooth muscle cell–specific (SM22-cre tg /TM flox/flox ) TM ablation and their respective wild-type controls (TM flox/flox and SM22-cre tg /TM +/+ ) were generated. In the mouse CaCl 2 -induced AAA model, deficiency of myeloid TM, but not vascular smooth muscle cell TM, inhibited macrophage accumulation, attenuated proinflammatory cytokine and matrix metalloproteinase-9 production, and finally mitigated elastin destruction and aortic dilatation. In vitro TM-deficient monocytes/macrophages, versus TM wild-type counterparts, exhibited attenuation of proinflammatory mediator expression, adhesion to endothelial cells, and generation of reactive oxygen species. Consistently, myeloid TM–deficient hyperlipidemic mice (ApoE −/− /LysMcre/TM flox/flox ) were resistant to AAA formation induced by angiotensin II infusion, along with reduced macrophage infiltration, suppressed matrix metalloproteinase activities, and diminished oxidative stress. Conclusions— Membrane-bound TM in macrophages plays an essential role in the development of AAA by enhancing proinflammatory mediator elaboration, macrophage recruitment, and oxidative stress.

Objectives We investigated whether naloxone could reduce macrophage activation and influence atherosclerotic lesion formation in mice. Background Macrophages play an important role in the inflammatory process in atherosclerosis. Naloxone could inhibit activation of microglia, the resident macrophage in the nervous system. Methods The anti-inflammatory effect of naloxone was evaluated by stimulating the macrophage cell culture and FVB mice with lipopolysaccharide or oxidized low-density lipoprotein with and without naloxone pretreatment. Apolipoprotein-E (apoE)-deficient mice received naloxone injection for 10 weeks, and the severity of aortic atherosclerosis was measured. The left common carotid arteries of C57BL/6 mice were ligated near the carotid bifurcation. The mice then received naloxone injection for 4 weeks after ligation, and the severity of neointima formation was evaluated. Results Naloxone pretreatment significantly suppressed the production of tumor necrosis factor-α (TNF-α), interleukin-6, monocyte chemoattractant protein-1, and superoxide in macrophages after stimulation. In FVB mice, naloxone reduced the TNF-α level in circulation, inflammatory cell infiltration in lungs, and superoxide production in aorta. Naloxone injection significantly decreased the severity of aortic atherosclerosis in the apoE-deficient mice and carotid neointima formation in the C57BL/6 mice after ligation. Conclusions Naloxone, with its novel anti-inflammatory effect, significantly reduces atherosclerosis and neointima formation in mice.

Summary. Background: Oxidation of low density lipoproteins is an initial step of atherogenesis that generates pro-inflammatory phospholipids, including platelet-activating factor (PAF). PAF is degraded by PAF-acetylhydrolase (PAF-AH), which has been postulated to be a risk factor for myocardial infarction (MI). The role of PAF-AH for the onset of premature MI is unclear. Methods: Polymorphisms located in putatively functional regions were investigated in a cohort of patients having premature MI onset prior to 46 years of age (n = 200) and a sex-age-matched control group (n = 200). The activity of PAF-AH and coronary angiograms were evaluated for the severity of coronary atherosclerosis. Results: The V allele of A379V (exon 11) polymorphism on PAF-AH gene was more frequent in patients with premature MI (P = 0.001). This V allele polymorphism was also associated with a lower activity of plasma PAF-AH and a more complex coronary atherosclerosis (p Trends

Background— Thrombomodulin is an anticoagulant, endothelial-cell-membrane glycoprotein. A recombinant thrombomodulin domain containing 6 epidermal growth factor–like structures exhibits mitogenic activity. This study explored the novel angiogenic effects of the recombinant domain using in vitro and in vivo models. Methods and Results— Human recombinant thrombomodulin containing 6 epidermal growth factor–like structures (TMD2) and TMD2 plus a serine and threonine-rich domain (TMD23) were prepared using the Pichia pastoris expression system. Combined with purified TMD2 or TMD23, thrombin effectively activated protein C. TMD23 had higher activity than TMD2 in stimulating DNA synthesis in cultured human umbilical vein endothelial cells. Additionally, TMD23 stimulated chemotactic motility and capillarylike tube formation in human umbilical vein endothelial cells, an effect mediated through phosphorylation of extracellular signal–regulated kinase 1/2 and p38 mitogen-activated protein kinase and the phosphatidylinositol-3 kinase/Akt/endothelial nitric oxide synthase pathway. TMD23 also stimulated endothelial cell expression of matrix metalloproteinases and plasminogen activators, which mediated extracellular proteolysis, leading to endothelial cell invasion and migration during angiogenesis. Furthermore, TMD23-containing implants in rat cornea induced ingrowth of new blood vessels from the limbus. With the murine angiogenesis assay, TMD23 not only induced neovascularization coinjected with Matrigel and heparin but also enhanced angiogenesis in Matrigel containing melanoma A2058 cells in nude mice. Conclusions— The recombinant thrombomodulin domain TMD23 enhanced the angiogenic response in vitro and in vivo, suggesting that thrombomodulin fragments may play a role in the formation of new vessels. These findings may provide a new therapeutic option for treating ischemic diseases.