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Down syndrome critical region gene 1 (DSCR-1) short variant (DSCR-1s) is an inhibitor of calcineurin/NFAT signaling encoded by exons 4-7 of DSCR1. We previously reported that VEGF induces DSCR-1s expression in endothelial cells, which in turn negatively feeds back to attenuate endothelial cell activation. Here, in order to characterize the role of the promoter that drives DSCR-1s expression in mediating inducible expression in vivo and to determine the functional relevance of DSCR-1s in inflammation, we targeted a DNA construct containing 1.7 kb of the human DSCR1s promoter coupled to the lacZ reporter to the hypoxanthine guanine phosphoribosyl transferase (Hprt) locus of mice. We determined that lacZ was uniformly expressed in the endothelium of transgenic embryos but was markedly downregulated postnatally. Systemic administration of VEGF or LPS in adult mice resulted in cyclosporine A--sensitive reactivation of the DSCR1s promoter and endogenous gene expression in a subset of organs, including the heart and brain. The DSCR1s promoter was similarly induced in the endothelium of tumor xenografts. In a mouse model of endotoxemia, DSCR-1s--deficient mice demonstrated increased sepsis mortality, whereas adenovirus-mediated DSCR-1s overexpression protected against LPS-induced lethality. Collectively, these data suggest that the DSCR1s promoter directs vascular bed--specific expression in activated endothelium and that DSCR-1s serves to dampen the host response to infection., Introduction Endothelial cell phenotypes vary in structure and function, in space and time, and in health and disease (reviewed in refs. (1), (2)). Endothelial cells are adapted to meet the [...]

The last common ancestor of hagfish and gnathostomes was also the last common ancestor of all extant vertebrates that lived some time more than 500 million years ago. Features that are shared between hagfish and gnathostomes can be inferred to have already been present in this ancestral vertebrate. We recently reported that hagfish endothelium displays phenotypic heterogeneity in ultrastructure, lectin binding, and mechanisms of leukocyte adhesion. Thus, phenotypic cell heterogeneity evolved as an early feature of the endothelium. In the present study, we wanted to extend these observations by determining whether hagfish endothelium plays a role in mediating vasomotor tone. Response of mesenteric and skeletal muscle arteries to a variety of mediators was assayed by videomicroscopy. Phenylephrine and acetylcholine induced vasoconstriction of mesenteric and skeletal muscle arteries. Bradykinin (BK) and ADP promoted vasorelaxation in precontracted mesenteric arteries but not those from skeletal muscle. BK- and ADP-mediated vasorelaxation of the mesenteric artery was abrogated by mechanical denudation of the endothelium but was unaffected by [N.sup.G]-nitro-L-arginine methyl ester. Indomethacin significantly inhibited the vasodilatory response to ADP but not BK. The nitric oxide donor sodium nitroprusside resulted in endothelium-independent relaxation of both mesenteric and skeletal muscle arteries. Together, these data suggest that site-specifc endothelium-dependent vasorelaxation is an evolutionarily conserved property of this cell lineage. endothelium; hagfish; vasomotor tone

Abstract: Background: Early recognition of acute organ dysfunction in emergency department (ED) patients with suspected infection may help select patients at increased risk of mortality. The hematologic system is often overlooked in the evaluation and management of patients with infection because it is poorly circumscribed and serves a multitude of functions. Study Objectives: We examine the hypothesis that abnormalities in commonly and easily obtained markers of coagulation function (international normalized ratio [INR], partial thromboplastin time [PTT], and platelet count [PLT]) are associated with mortality in ED patients admitted to the hospital with suspected infection. Methods: Design: Secondary analysis of a prospective observational cohort study. Setting: Urban tertiary care university hospital with 50,000 annual ED visits. Patients: Included patients: adults (age 18 ≥ years) evaluated in the ED for a suspected infection, had an INR, PTT, and PLT obtained during the ED stay, admitted to the hospital. Excluded patients: on oral anticoagulant therapy, received heparin, or pre-existing severe liver disease. Results: There were 1688 patients included. The in-hospital mortality rate was 5.9%. After adjusting for elderly status, comorbid illness burden, and severity of illness, elevated INR was associated with a 2.9 (95% confidence interval [CI] 1.6–5.2) increased odds of death, and a low platelet count (< 150,000/uL) was associated with 2.0 (95% CI 1.2–3.3) increased odds of death. The C-statistic for the model was 0.80. Conclusion: We found an independent association between abnormalities in the coagulation system and mortality in ED patients with suspected infection. These findings underscore the close interaction between inflammation and coagulation and provide evidence that these simple laboratory tests should be routinely considered during the early evaluation of the infected patient. [Copyright &y& Elsevier]

The article presents a study which characterizes the role of ETS-Related Gene (ERG) in the regulation of endothelial cells (EC) function through RNA interference. It mentions that ERG plays a role as a transcriptional repressor of interleukin (IL)-8 in ECs. It also states that it serves as a regulator of EC-restricted genes such as VE-cadherin, von Willebrand factor, and endoglin. Further, ERG portrays a more EC-restricted pattern of expression in cultured cells and in vivo in different organs.

The last common ancestor of hagfish and gnathostomes was also the last common ancestor of all extant vertebrates that lived some time more than 500 million years ago. Features that are shared between hagfish and gnathostomes can be inferred to have already been present in this ancestral vertebrate. We recently reported that hagfish endothelium displays phenotypic heterogeneity in ultrastructure, lectin binding, and mechanisms of leukocyte adhesion. Thus, phenotypic cell heterogeneity evolved as an early feature of the endothelium. In the present study, we wanted to extend these observations by determining whether hagfish endothelium plays a role in mediating vasomotor tone. Response of mesenteric and skeletal muscle arteries to a variety of mediators was assayed by videomicroscopy. Phenylephrine and acetylcholine induced vasoconstriction of mesenteric and skeletal muscle arteries. Bradykinin (BK) and ADP promoted vasorelaxation in precontracted mesenteric arteries but not those from skeletal muscle. BK- and ADP-mediated vasorelaxation of the mesenteric artery was abrogated by mechanical denudation of the endothelium but was unaffected by Nω-nitro-L-arginine methyl ester. Indomethacin significantly inhibited the vasodilatory response to ADP but not BK. The nitric oxide donor sodium nitroprusside resulted in endothelium-independent relaxation of both mesenteric and skeletal muscle arteries. Together, these data suggest that site-specific endothelium-dependent vasorelaxation is an evolutionarily conserved property of this cell lineage. [ABSTRACT FROM AUTHOR]

Sepsis, the systemic inflammatory response to infection, is a leading cause of morbidity and mortality. The mechanisms of sepsis pathophysiology remain obscure but are likely to involve a complex interplay between mediators of the inflammatory and coagulation pathways. An improved understanding of these mechanisms should provide an important foundation for developing novel therapies. In this study, we show that sepsis is associated with a time-dependent increase in circulating levels of vascular endothelial growth factor (VEGF) and placental growth factor (PIGF) in animal and human models of sepsis. Adenovirus-mediated overexpression of soluble Fit-1 (sFlt-1) in a mouse model of endotoxemia attenuated the rise in VEGF and PIGF levels and blocked the effect of endotoxemia on cardiac function, vascular permeability, and mortality. Similarly, in a cecal ligation puncture (CLP) model, adenovirus-sFlt-1 protected against cardiac dysfunction and mortality. When administered in a therapeutic regimen beginning 1 h after the onset of endotoxemia or CLP, sFlt peptide resulted in marked improvement in cardiac physiology and survival. Systemic administration of antibodies against the transmembrane receptor Flk-1 but not Flt-1 protected against sepsis mortality. Adenovirus-mediated overexpression of VEGF but not PIGF exacerbated the lipopolysaccharide-mediated toxic effects. Together, these data support a pathophysiological role for VEGF in mediating the sepsis phenotype. [ABSTRACT FROM AUTHOR]

Vascular smooth muscle cell (VSMC) proliferation and migration contribute significantly to atherosclerosis, postangioplasty restenosis, and transplant vasculopathy. Forkhead transcription factors belonging to the FoxO subfamily have been shown to inhibit growth and cell cycle progression in a variety of cell types. We hypothesized that forkhead proteins may play a role in VSMC biology. Under in vitro conditions, platelet-derived growth factor (PDGF)-BB, tumor necrosis factor-α, and insulin-like growth factor 1 stimulated phosphorylation of FoxO in human coronary artery smooth muscle cells via MEK½ and/or phosphatidylinositol 3-kinase-dependent signaling pathways. PDGF-BB, tumor necrosis factor-α, and insulin-like growth factor 1 treatment resulted in the nuclear exclusion of FoxO, whereas PDGF-BB alone down-regulated the FoxO target gene, p27 kip1, and enhanced cell survival and progression through the cell cycle. These effects were abrogated by overexpression of a constitutively active, phosphorylation-resistant mutant of the FoxO family member, TM-FKHRL1. The anti-proliferative effect of TM-FKHRL1 was partially reversed by small interfering RNA against p27kip1. In a rat balloon carotid arterial injury model, adenovirus-mediated gene transfer of FKHRL1 caused an increase in the expression of p27kip1 in the VSMC and inhibition of neointimal hyperplasia. These data suggest that FoxO activity inhibits VSMC proliferation and activation and that this signaling axis may represent a therapeutic target in vasculopathic disease states. [ABSTRACT FROM AUTHOR]

The function of the endogenous angiogenesis inhibitor thrombospondin-1 (TSP-1) in tissue repair has remained controversial. We established transgenic mice with targeted overexpression of TSP-1 in the skin, using a keratin 14 expression cassette. TSP-1 transgenic mice were healthy and fertile, and did not show any major abnormalities of normal skin vascularity, cutaneous vascular architecture, or microvascular permeability. However, healing of full-thickness skin wounds was greatly delayed in TSP-1 transgenic mice and was associated with reduced granulation tissue formation and highly diminished wound angiogenesis. Moreover, TSP-1 potently inhibited libroblast migration/n vivo and in vitro. These findings demonstrate that TSP-1 preferentially interfered with wound healing-associated angiogenesis, rather than with the angiogenesis associated with normal development and skin homeostasis, and suggest that therapeutic application of angiogenesis inhibitors might potentially be associated with impaired wound vascularization and tissue repair. [ABSTRACT FROM AUTHOR]

Abstract: Endothelial cell phenotypes are differentially regulated between different sites of the vascular tree. We tested the hypothesis that endocan, a novel soluble dermatan sulfate proteoglycan, is differentially expressed in the intact endothelium and that site-specific expression is mediated by signals in the local microenvironment. Using a combination of Northern blot analyses, Taqman RT-PCR, and in situ hybridizations, endocan was shown to be preferentially expressed in the endothelial lining of tumor xenografts, including human non-small cell lung cancer, rat glioma, and human renal cell carcinoma. In contrast, endocan mRNA was expressed at low levels in embryos between E4.5 and E18.5. Under in vitro conditions, endocan expression in human umbilical vein endothelial cells (HUVEC) was upregulated by tumor cell-conditioned medium, an effect that was inhibited by the addition of neutralizing antibody to vascular endothelial growth factor (VEGF). Moreover, treatment of HUVEC with VEGF resulted in a dose- and time-dependent increase in endocan mRNA. The results suggest that endocan is preferentially expressed in tumor endothelium in vivo and that its expression is regulated by tumor-derived factors. [Copyright &y& Elsevier]

The endothelium, as the interface between blood and all tissues, plays a critical role in inflammation. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid, highly abundant in plasma, that potently regulates endothelial responses through interaction with its receptors (S1 PRs). Here, we studied the role of S1PR2 in the regulation of the proadhesion and proinflammatory phenotype of the endothelium. By using genetic approaches and a S1PR2-specific antagonist (JTE013), we found that S1PR2 plays a key role in the permeability and inflammatory responses of the vascular endothelium during endotox-emia. Experiments with bone marrow chimeras (S1pr2+/+ →S1pr2+/+, S1pr2+/+ → S1pr2-/-, and S1pr2-/- → S1pr2+/+) indicate the critical role of S1PR2 in the stromal compartment, in the regulation of vascular permeability and vascular inflammation. In vitro, JTE013 potently inhibited tumor necrosis factor α-induced endothelial inflammation. Finally, we provide detailed mechanisms on the downstream signaling of S1PR2 in vascular inflammation that include the activation of the stress-activated protein kinase pathway that, together with the Rho-kinase nuclear factor kappa B pathway (NF-kB), are required for S1 PR2-mediated endothelial inflammatory responses. Taken together, our data indicate that S1PR2 is a key regulator of the proinflammatory phenotype of the endothelium and identify S1PR2 as a novel therapeutic target for vascular disorders. [ABSTRACT FROM AUTHOR]

Endothelial phenotypes are highly regulated in space and time by both transcriptional and post-transcriptional mechanisms. There is increasing evidence that the GATA family of transcription factors function as signal transducers, coupling changes in the extracellular environment to changes in downstream target gene expression. Here we show that human primary endothelial cells derived from large blood vessels express GATA2, -3, and -6. Of these factors, GATA3 was expressed at the highest levels. In DNA microarrays of human umbilical vein endothelial cells (HUVEC), small interfering RNA-mediated knockdown of GATA3 resulted in reduced expression of genes associated with angiogenesis, including Tie2. At a functional level, GATA3 knockdown inhibited angiopoietin (Ang)1-mediated but not vascular endothelial cell growth factor (VEGF)-mediated AKT signaling, cell migration, survival, and tube formation. In electrophoretic gel mobility shift assays and chromatin immunoprecipitation, GATA3 was shown to bind to regulatory regions within the 5'-untranslated region of the Tie2 gene. In co-immunoprecipitation and co-transfection assays, GATA3 and the Ets transcription factor, ELF 1, physically interacted and synergized to transactivate the Tie2 promoter. GATA3 knockdown blocked the ability of Ang1 to attenuate vascular endothelial cell growth factor stimulation of vascular cell adhesion molecule-1 expression and monocytic cell adhesion. Moreover, exposure of human umbilical vein endothelial cells to tumor necrosis factor-α resulted in marked down-regulation of GATA3 expression and reduction in Tie2 expression. Together, these findings suggest that GATA3 is indispensable for Ang-1-Tie2-mediated signaling in large vessel endothelial cells. [ABSTRACT FROM AUTHOR]

Hair follicle regeneration involves epithelial–mesenchymal interactions (EMIs) of follicular epithelial and dermal papilla (DP) cells. Co-grafting of those cellular components from mice allows complete hair reconstitution. However, regeneration of human hair in a similar manner has not been reported. Here, we investigated the possibility of cell-based hair generation from human cells. We found that DP-enriched cells (DPE) are more critical than epidermal cells in murine hair reconstitution on a cell number basis, and that murine DPE are also competent for hair regeneration with rat epidermal cells. Co-grafting of human keratinocytes derived from neonatal foreskins with murine DPE produced hair follicle-like structures consisting of multiple epidermal cell layers with a well-keratinized innermost region. Those structures expressed hair follicle-specific markers including hair keratin, and markers expressed during developmental stages. However, the lack of regular hair structures indicates abnormal folliculogenesis. Similar hair follicle-like structures were also generated with cultured human keratinocytes after the first passage, or with keratinocytes derived from adult foreskins, demonstrating that epidermal cells even at a mature stage can differentiate in response to inductive signals from DP cells. This study emphasizes the importance of EMI in follicular generation and the differentiation potential of epidermal keratinocytes.Journal of Investigative Dermatology (2007) 127, 2106–2115; doi:10.1038/sj.jid.5700823; published online 12 April 2007 [ABSTRACT FROM AUTHOR]

Roundabout guidance receptor 4 (Robo4) is an endothelial cell-specific receptor that stabilizes the vasculature in pathological angiogenesis. Although Robo4 has been shown to suppress vascular hyperpermeability induced by vascular endothelial growth factor (VEGF) in angiogenesis, the role of Robo4 in inflammation is poorly understood. In this study, we investigated the role of Robo4 in vascular hyperpermeability during inflammation. Endotoxemia models using Robo4 -/- mice showed increased mortality and vascular leakage. In endothelial cells, Robo4 suppressed tumor necrosis factor α (TNFα)-induced hyperpermeability by stabilizing VE-cadherin at cell junctions, and deletion assays revealed that the C-terminus of Robo4 was involved in this suppression. Through binding and localization assays, we demonstrated that in endothelial cells, Robo4 binds to TNF receptor-associated factor 7 (TRAF7) through interaction with the C-terminus of Robo4. Gain- and loss-of-function studies of TRAF7 with or without Robo4 expression showed that TRAF7 is required for Robo4-mediated suppression of hyperpermeability. Taken together, our results demonstrate that the Robo4-TRAF7 complex is a novel negative regulator of inflammatory hyperpermeability. We propose this complex as a potential future target for protection against inflammatory diseases., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)

The vascular barrier is an important function of the endothelium and its dysfunction is involved in several diseases. The barrier function of the endothelial cell monolayer is governed by cell-cell, cell-extracellular matrix (cell-ECM) contacts, and inflammatory factors such as thrombin, histamine or vascular endothelial growth factor. Several in vivo and in vitro assays that measure the vascular permeability induced by these factors have been developed. However, they suffer limitations such as being challenging for assessing details of biological processes at a cellular level or lacking the architecture of a vessel, that raise the need for new methods. In vitro 3D model-based assays have thus been developed but assays for investigating compounds that protects the barrier function are lacking. Here we describe the development of an in vitro three-dimensional (3D) vascular endothelium model in which we can manipulate the endothelial barrier function and permeability to molecules, which have a molecular weight similar to human serum albumin, allowing to assess the protective effect of compounds. A microvessel was prepared by culturing human umbilical vein endothelial cells (HUVECs) within a collagen gel on a polydimethylsiloxane (PDMS) chip. Using fluorescein isothiocyanate (FITC)-conjugated dextran (70 kDa, FITC-dextran) and confocal fluorescence microscopy, we showed that the microvessel presented an effective barrier function. We were then able to induce the loss of this barrier function by treatment with the inflammatory factor thrombin. The loss of barrier function was quantified by the extravasation of FITC-dextran into collagen matrix. Furthermore, we were able to analyze the protective effect on the endothelial barrier function of the cyclic adenosine monophosphate (cAMP) analog, 8-pCPT-2'-O-Me-cAMP (also called 007). In an attempt to understand the effects of thrombin and 007 in our model, we analyzed the adherens junctions and cytoskeleton through immunostaining of the vascular endothelial cadherin and actin, respectively. Our assay method could be used to screen for compounds modulating the barrier function of endothelial cells, as well as investigating mechanistic aspects of barrier dysfunction., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

The adipose-derived hormone leptin is well known for its contribution to energy metabolism and satiety signaling in the hypothalamus. Previous studies suggested that obesity is an independent risk factor for sepsis morbidity and mortality, and it is associated with elevated baseline levels of circulating leptin in normal, nonseptic patients. In mouse endotoxemia and cecal ligation puncture models of sepsis, we observed elevated levels of leptin and soluble leptin receptor (sLR). Exogenously administered leptin increased mortality in endotoxemia and cecal ligation puncture models and was associated with increased expression of adhesion and coagulation molecules, macrophage infiltration into the liver and kidney, and endothelial barrier dysfunction. Conversely, longform leptin receptor-deficient mice were protected from sepsis morbidity and mortality and had less endothelial dysfunction. Furthermore, an in vitro study revealed that leptin-induced endothelial dysfunction is likely mediated, at least in part, by monocytes. Moreover, administration of an sLR conferred a survival benefit. Human septic patients have increased circulating sLR concentrations, which were correlated with disease severity indices. Together, these data support a pathogenic role for leptin signaling during sepsis.

Introduction: Previous reports suggest that endothelial activation is an important process in sepsis pathogenesis. We investigated the association between biomarkers of endothelial cell activation and sepsis severity, organ dysfunction sequential organ failure assessment (SOFA) score, and death., Methods: This is a prospective, observational study including adult patients (age 18 years or older) presenting with clinical suspicion of infection to the emergency department (ED) of an urban, academic medical center between February 2005 and November 2008. Blood was sampled during the ED visit and biomarkers of endothelial cell activation, namely soluble fms-like tyrosine kinase-1 (sFlt-1), plasminogen activator inhibitors -1 (PAI-1), sE-selectin, soluble intercellular adhesion molecule (sICAM-1), and soluble vascular cell adhesion molecule (sVCAM-1), were assayed. The association between biomarkers and the outcomes of sepsis severity, organ dysfunction, and in-hospital mortality were analyzed., Results: A total of 221 patients were included: sepsis without organ dysfunction was present in 32%, severe sepsis without shock in 30%, septic shock in 32%, and 6% were non-infected control ED patients. There was a relationship between all target biomarkers (sFlt-1, PAI-1, sE-selectin, sICAM-1, and sVCAM-1) and sepsis severity, P < 0.05. We found a significant inter-correlation between all biomarkers, including the strongest correlations between sFlt-1 and sE-selectin (r = 0.55, P < 0.001), and between sFlt-1 and PAI-1 (0.56, P < 0.001). Among the endothelial cell activation biomarkers, sFlt-1 had the strongest association with SOFA score (r = 0.66, P < 0.001), the highest area under the receiver operator characteristic curve for severe sepsis of 0.82, and for mortality of 0.91., Conclusions: Markers of endothelial cell activation are associated with sepsis severity, organ dysfunction and mortality. An improved understanding of endothelial response and associated biomarkers may lead to strategies to more accurately predict outcome and develop novel endothelium-directed therapies in sepsis.

Endothelial phenotypes are highly regulated in space and time by both transcriptional and post-transcriptional mechanisms. There is increasing evidence that the GATA family of transcription factors function as signal transducers, coupling changes in the extracellular environment to changes in downstream target gene expression. Here we show that human primary endothelial cells derived from large blood vessels express GATA2, -3, and -6. Of these factors, GATA3 was expressed at the highest levels. In DNA microarrays of human umbilical vein endothelial cells (HUVEC), small interfering RNA-mediated knockdown of GATA3 resulted in reduced expression of genes associated with angiogenesis, including Tie2. At a functional level, GATA3 knockdown inhibited angiopoietin (Ang)-1-mediated but not vascular endothelial cell growth factor (VEGF)-mediated AKT signaling, cell migration, survival, and tube formation. In electrophoretic gel mobility shift assays and chromatin immunoprecipitation, GATA3 was shown to bind to regulatory regions within the 5'-untranslated region of the Tie2 gene. In co-immunoprecipitation and co-transfection assays, GATA3 and the Ets transcription factor, ELF1, physically interacted and synergized to transactivate the Tie2 promoter. GATA3 knockdown blocked the ability of Ang-1 to attenuate vascular endothelial cell growth factor stimulation of vascular cell adhesion molecule-1 expression and monocytic cell adhesion. Moreover, exposure of human umbilical vein endothelial cells to tumor necrosis factor-alpha resulted in marked down-regulation of GATA3 expression and reduction in Tie2 expression. Together, these findings suggest that GATA3 is indispensable for Ang-1-Tie2-mediated signaling in large vessel endothelial cells.

Recently, we demonstrated that circulating levels of vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) are increased in sepsis (Yano, K., P.C. Liaw, J.M. Mullington, S.C. Shih, H. Okada, N. Bodyak, P.M. Kang, L. Toltl, B. Belikoff, J. Buras, et al. 2006. J. Exp. Med. 203:1447-1458). Moreover, enhanced VEGF/Flk-1 signaling was shown to contribute to sepsis morbidity and mortality. We tested the hypothesis that PlGF also contributes to sepsis outcome. In mouse models of endotoxemia and cecal ligation puncture, the genetic absence of PlGF or the systemic administration of neutralizing anti-PlGF antibodies resulted in higher mortality compared with wild-type or immunoglobulin G-injected controls, respectively. The increased mortality associated with genetic deficiency of PlGF was reversed by adenovirus (Ad)-mediated overexpression of PlGF. In the endotoxemia model, PlGF deficiency was associated with elevated circulating levels of VEGF, induction of VEGF expression in the liver, impaired cardiac function, and organ-specific accentuation of barrier dysfunction and inflammation. Mortality of endotoxemic PlGF-deficient mice was increased by Ad-mediated overexpression of VEGF and was blocked by expression of soluble Flt-1. Collectively, these data suggest that up-regulation of PlGF in sepsis is an adaptive host response that exerts its benefit, at least in part, by attenuating VEGF signaling.

Mammalian endothelial cells (ECs) display marked phenotypic heterogeneity. Little is known about the evolutionary mechanisms underlying EC heterogeneity. The last common ancestor of hagfish and gnathostomes was also the last common ancestor of all extant vertebrates, which lived some time more than 500 million years ago. Features of ECs that are shared between hagfish and gnathostomes can be inferred to have already been present in this ancestral vertebrate. The goal of this study was to determine whether the hagfish endothelium displays phenotypic heterogeneity. Electron microscopy of the aorta, dermis, heart, and liver revealed ultrastructural heterogeneity of the endothelium. Immunofluorescent studies demonstrated marked differences in lectin binding between vascular beds. Intravital microscopy of the dermis revealed histamine-induced adhesion of leukocytes in capillaries and postcapillary venules, but no such adhesion in arterioles. Together, these data suggest that structural, molecular, and functional heterogeneity of the endothelium evolved as an early feature of this cell lineage.

Objective: Tumor necrosis factor (TNF)-alpha initiates numerous changes in endothelial cell (EC) gene expression that contributes to the pathology of various diseases including inflammation. We hypothesized that TNF-alpha-mediated gene induction involves multiple signaling pathways, and that inhibition of one or more of these pathways may selectively target subsets of TNF-alpha-responsive genes and functions., Methods and Results: Human umbilical vein endothelial cells (ECs) were preincubated with inhibitors of PI3 kinase (LY294002), histone deacetylases (HDAC) (trichostatin A [TSA]), de novo protein synthesis (CHX), proteasome (MG-132), and GATA factors (K-11430) before exposure to TNF-alpha at 4 hours and analyzed by microarray. TNF-alpha-mediated induction of vascular cell adhesion molecule-1 (VCAM-1) was attenuated by all of these inhibitors, whereas in contrast, stimulation of intercellular adhesion molecule-1 (ICAM-1) was blocked by MG-132 alone. Moreover TSA blocked TNF-alpha-mediated induction of monocyte adhesion both in vitro and in vivo through the suppression of VCAM-1. Further analysis demonstrated that HDAC3 plays a significant role in the regulation of TNF-alpha-mediated VCAM-1 expression., Conclusions: TNF-alpha activates ECs via multiple signaling pathways, and these pathways may be selectively targeted to modulate EC function. Moreover, TSA treatment reduced monocyte adhesion via VCAM-1 suppression in vitro and in vivo, suggesting that TSA might be useful for the attenuation of the inflammatory response in EC.