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Endothelial Protein C Receptor Expression is Regulated by Sp1 Transcription Factor in Murine Microglia. JOURNAL OF BASIC AND CLINICAL HEALTH SCIENCES 2021. [DOI: 10.30621/jbachs.854244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Salvaris EJ, Moran CJ, Roussel JC, Fisicaro N, Robson SC, Cowan PJ. Pig endothelial protein C receptor is functionally compatible with the human protein C pathway. Xenotransplantation 2019; 27:e12557. [DOI: 10.1111/xen.12557] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/12/2019] [Accepted: 09/11/2019] [Indexed: 11/28/2022]
Affiliation(s)
- Evelyn J. Salvaris
- Immunology Research Centre St. Vincent's Hospital Melbourne Victoria Australia
| | | | | | - Nella Fisicaro
- Immunology Research Centre St. Vincent's Hospital Melbourne Victoria Australia
| | - Simon C. Robson
- Beth Israel Deaconess Medical Center Harvard Medical School Boston MA USA
| | - Peter J. Cowan
- Immunology Research Centre St. Vincent's Hospital Melbourne Victoria Australia
- Department of Medicine University of Melbourne Melbourne Victoria Australia
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Schuldt K, Ehmen C, Evans J, May J, Ansong D, Sievertsen J, Muntau B, Ruge G, Agbenyega T, Horstmann RD. Endothelial protein C receptor gene variants not associated with severe malaria in ghanaian children. PLoS One 2014; 9:e115770. [PMID: 25541704 PMCID: PMC4277309 DOI: 10.1371/journal.pone.0115770] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 11/27/2014] [Indexed: 12/03/2022] Open
Abstract
Background Two recent reports have identified the Endothelial Protein C Receptor (EPCR) as a key molecule implicated in severe malaria pathology. First, it was shown that EPCR in the human microvasculature mediates sequestration of Plasmodium falciparum-infected erythrocytes. Second, microvascular thrombosis, one of the major processes causing cerebral malaria, was linked to a reduction in EPCR expression in cerebral endothelial layers. It was speculated that genetic variation affecting EPCR functionality could influence susceptibility to severe malaria phenotypes, rendering PROCR, the gene encoding EPCR, a promising candidate for an association study. Methods Here, we performed an association study including high-resolution variant discovery of rare and frequent genetic variants in the PROCR gene. The study group, which previously has proven to be a valuable tool for studying the genetics of malaria, comprised 1,905 severe malaria cases aged 1–156 months and 1,866 apparently healthy children aged 2–161 months from the Ashanti Region in Ghana, West Africa, where malaria is highly endemic. Association of genetic variation with severe malaria phenotypes was examined on the basis of single variants, reconstructed haplotypes, and rare variant analyses. Results A total of 41 genetic variants were detected in regulatory and coding regions of PROCR, 17 of which were previously unknown genetic variants. In association tests, none of the single variants, haplotypes or rare variants showed evidence for an association with severe malaria, cerebral malaria, or severe malaria anemia. Conclusion Here we present the first analysis of genetic variation in the PROCR gene in the context of severe malaria in African subjects and show that genetic variation in the PROCR gene in our study population does not influence susceptibility to major severe malaria phenotypes.
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Affiliation(s)
- Kathrin Schuldt
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- * E-mail:
| | - Christa Ehmen
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Jennifer Evans
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Juergen May
- Infectious Disease Epidemiology Group, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Daniel Ansong
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Juergen Sievertsen
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Birgit Muntau
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Gerd Ruge
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Tsiri Agbenyega
- School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Rolf D. Horstmann
- Department of Molecular Medicine, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
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Moussiliou A, Alao MJ, Denoeud-Ndam L, Tahar R, Ezimegnon S, Sagbo G, Amoussou A, Luty AJF, Deloron P, Tuikue Ndam N. High plasma levels of soluble endothelial protein C receptor are associated with increased mortality among children with cerebral malaria in Benin. J Infect Dis 2014; 211:1484-8. [PMID: 25425698 DOI: 10.1093/infdis/jiu661] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 11/20/2014] [Indexed: 11/14/2022] Open
Abstract
Loss of endothelial protein C receptor (EPCR) occurs at the sites of Plasmodium falciparum-infected erythrocyte sequestration in patients with or who died from cerebral malaria. In children presenting with different clinical syndromes of malaria, we assessed the relationships between endogenous plasma soluble EPCR (sEPCR) levels and clinical presentation or mortality. After adjustment for age, for treatment before admission, and for a known genetic factor, sEPCR level at admission was positively associated with cerebral malaria (P = .011) and with malaria-related mortality (P = .0003). Measuring sEPCR levels at admission could provide an early biological marker of the outcome of cerebral malaria.
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Affiliation(s)
- Azizath Moussiliou
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT Université Pierre et Marie Curie, Paris, France
| | | | - Lise Denoeud-Ndam
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Rachida Tahar
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Sem Ezimegnon
- Centre d'Etude et de Recherche sur le paludisme associé à la Grossesse et à l'Enfance, Université d'Abomey-Calavi
| | - Gratien Sagbo
- Service de pédiatrie, Centre National Hospitalo-Universitaire
| | - Annick Amoussou
- Service de pédiatrie, Hôpital de zone de Suru-Léré, Cotonou, Bénin
| | - Adrian J F Luty
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Philippe Deloron
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
| | - Nicaise Tuikue Ndam
- PRES Sorbonne Paris Cité, Faculté de Pharmacie, Université Paris Descartes Institut de Recherche pour le Développement, UMR216-MERIT
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Ku SK, Han MS, Bae JS. Withaferin A is an inhibitor of endothelial protein C receptor shedding in vitro and in vivo. Food Chem Toxicol 2014; 68:23-9. [PMID: 24632454 DOI: 10.1016/j.fct.2014.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 03/04/2014] [Accepted: 03/05/2014] [Indexed: 11/25/2022]
Abstract
Withaferin A (WFA), an active compound from Withania somnifera, has been widely researched for its anti-inflammatory and cardioactive properties and effects on the central nervous system. The endothelial cell protein C receptor (EPCR) plays important roles in blood coagulation and inflammation. EPCR activity is markedly changed by ectodomain cleavage and release as the soluble EPCR. EPCR is shed from the cell surface, mediated by tumor necrosis factor-α converting enzyme (TACE). In this study, we investigated the effects of WFA on the EPCR shedding in human umbilical vein endothelial cells (HUVECs) and in mice and the associated signaling pathways. WFA was found to induce inhibition of phorbol-12-myristate 13-acetate (PMA), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and on cecal ligation and puncture (CLP)-induced EPCR shedding and WFA suppressed the expression and activity of TACE. In addition, treatment with WFA resulted in reduced PMA-stimulated phosphorylation of p38, extracellular regulated kinases (ERK) 1/2, and c-Jun N-terminal kinase (JNK). These results demonstrate a therapeutic potentiality of WFA as an anti-sEPCR shedding reagent against PMA and CLP-mediated EPCR shedding.
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Affiliation(s)
- Sae-Kwang Ku
- Department of Anatomy and Histology, College of Korean Medicine, Daegu Haany University, Gyeongsan 712-715, Republic of Korea
| | - Min-Su Han
- Laboratory for Arthritis and Bone Biology, Fatima Research Institute, Daegu Fatima Hospital, Daegu 701-724, Republic of Korea
| | - Jong-Sup Bae
- College of Pharmacy, CMRI, Research Institute of Pharmaceutical Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
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Ku SK, Lee W, Yoo H, Han CK, Bae JS. Inhibitory effects of epi-sesamin on endothelial protein C receptor shedding in vitro and in vivo. Inflamm Res 2013; 62:895-902. [PMID: 23884236 DOI: 10.1007/s00011-013-0648-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/16/2013] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE AND DESIGN Endothelial protein C receptor (EPCR) plays a pivotal role in augmenting Protein C activation by the thrombin-thrombomodulin complex. The activity of EPCR is markedly changed by ectodomain cleavage and release as the soluble protein (sEPCR). The EPCR shedding is mediated by the tumor necrosis factor-α converting enzyme (TACE). Epi-sesamin (ESM), from the roots of Asarum siebodlii, is known to exhibit anti-allergic and anti-fungal activities. However, little is known about the effects of ESM on EPCR shedding. METHODS We investigated this issue by monitoring the effects of ESM on phorbol-12-myristate 13-acetate (PMA), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and cecal ligation and puncture (CLP)-mediated EPCR shedding. RESULTS Data showed that ESM induced potent inhibition of PMA, TNF-α, IL-1β, and CLP-induced EPCR shedding, likely through suppression of TACE expression. In addition, treatment with ESM resulted in a reduction of PMA-stimulated phosphorylation of p38, extracellular regulated kinases (ERK) 1/2, and c-Jun N-terminal kinase (JNK). CONCLUSIONS Given these results, ESM should be viewed as a candidate therapeutic agent for treatment of various severe vascular inflammatory diseases via inhibition of EPCR shedding.
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Affiliation(s)
- Sae-Kwang Ku
- Department of Anatomy and Histology, College of Oriental Medicine, Daegu Haany University, Gyeongsan, 712-715, Republic of Korea
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Gleeson EM, O’Donnell JS, Preston RJS. The endothelial cell protein C receptor: cell surface conductor of cytoprotective coagulation factor signaling. Cell Mol Life Sci 2012; 69:717-26. [PMID: 21968919 PMCID: PMC11115159 DOI: 10.1007/s00018-011-0825-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 09/09/2011] [Accepted: 09/12/2011] [Indexed: 12/27/2022]
Abstract
Increasing evidence links blood coagulation proteins with the regulation of acute and chronic inflammatory disease. Of particular interest are vitamin K-dependent proteases, which are generated as a hemostatic response to vascular injury, but can also initiate signal transduction via interactions with vascular receptors. The endothelial cell protein C receptor (EPCR) is a multi-ligand vitamin K-dependent protein receptor for zymogen and activated forms of plasma protein C and factor VII. Although the physiological role of the EPCR-FVII(a) interaction is not well-understood, protein C binding to EPCR facilitates rapid generation of APC in response to excessive thrombin generation, and is a central requirement for the multiple signal-transduction cascades initiated by APC on both vascular endothelial and innate immune cells. Exciting recent studies have highlighted the emerging role of EPCR in modulating the cytoprotective properties of APC in a number of diverse inflammatory disorders. In this review, we describe the structure-function relationships, signal transduction pathways, and cellular interactions that enable EPCR to modulate the anticoagulant and anti-inflammatory properties of its vitamin K-dependent protein ligands, and examine the relevance of EPCR to both thrombotic and inflammation-associated disease.
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Affiliation(s)
- Eimear M. Gleeson
- Haemostasis Research Group, Department of Haematology, Institute of Molecular Medicine, St James Hospital Campus, Trinity College Dublin, Dublin, Ireland
| | - James S. O’Donnell
- Haemostasis Research Group, Department of Haematology, Institute of Molecular Medicine, St James Hospital Campus, Trinity College Dublin, Dublin, Ireland
| | - Roger J. S. Preston
- Haemostasis Research Group, Department of Haematology, Institute of Molecular Medicine, St James Hospital Campus, Trinity College Dublin, Dublin, Ireland
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Navarro S, Bonet E, Estellés A, Montes R, Hermida J, Martos L, España F, Medina P. The endothelial cell protein C receptor: Its role in thrombosis. Thromb Res 2011; 128:410-6. [DOI: 10.1016/j.thromres.2011.08.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 07/14/2011] [Accepted: 08/01/2011] [Indexed: 12/01/2022]
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Alternative mRNA is favored by the A3 haplotype of the EPCR gene PROCR and generates a novel soluble form of EPCR in plasma. Blood 2007; 111:3442-51. [PMID: 18073349 DOI: 10.1182/blood-2007-08-104968] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The endothelial cell protein C receptor also exists in soluble form in plasma (sEPCR), resulting from ADAM17 cleavage. Elevated sEPCR levels are observed in subjects carrying the A3 haplotype, which is characterized by a Ser219Gly substitution in the transmembrane domain, rendering the receptor more sensitive to cleavage. Because sEPCR production is not completely blocked by metalloprotease inhibition, we looked for another mechanism. Comparing mRNA expression patterns and levels in A3 and non-A3 cells from 32 human umbilical cord veins, we detected a truncated mRNA in addition to the full-length mRNA. This truncated mRNA was 16 times more abundant in A3 human umbilical vein endothelial cells than in non-A3 human umbilical vein endothelial cells and encoded a protein lacking the transmembrane domain. We stably expressed a recombinant form of this protein (rEPCRisoform) and a protein mimicking the plasma sEPCR (rEPCRsol). Functional studies of the purified recombinant proteins revealed that the rEPCRisoform bound to recombinant protein C with similar affinity than rEPCRsol and that it also inhibited the anticoagulant activity of APC. Trace amounts of the EPCR isoform were found in the plasma of A3 subjects. These results suggest that the sEPCRisoform could contribute to the regulatory effect of sEPCR in plasma.
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Mollica LR, Crawley JTB, Liu K, Rance JB, Cockerill PN, Follows GA, Landry JR, Wells DJ, Lane DA. Role of a 5′-enhancer in the transcriptional regulation of the human endothelial cell protein C receptor gene. Blood 2006; 108:1251-9. [PMID: 16627757 DOI: 10.1182/blood-2006-02-001461] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
AbstractThe endothelial cell protein C receptor (EPCR) is expressed by endothelial cells of large blood vessels and by hematopoietic stem cells. DNaseI hypersensitive (DH) site mapping across 38 kb of the human EPCR gene (hEPCR) locus identified 3 potential regulatory elements. By itself, the DH region spanning the proximal promoter (PP) was unable to direct cell-specific transcription in transgenic mice. A second DH element, located upstream of PP and termed –5.5HS was hypersensitive only in endothelial cells (ECs) and immature hematopoietic cell lines. Transgenes expressing LacZ under the control of –5.5HS coupled to either PP or the SV40 promoter were able to direct β-galactosidase activity to the endothelium of large vessels during embryogenesis and adulthood. The –5.5HS exhibited enhancer activity that was conferred by the interplay of transcription factors interacting with conserved Ets and composite GATA/Tal1 motifs. The third DH element, located in intron 2, was primarily hypersensitive in EPCR-negative cells, and capable of initiating antisense transcription, suggesting a role in hEPCR silencing. This study identifies critical elements required for the tissue specificity of hEPCR and suggests a mechanism for endothelial and hematopoietic stem cell–specific transcriptional regulation that reflects the common origin of these cell types.
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Maruoka T, Tanabe H, Chiba M, Kasahara M. Chicken CD1 genes are located in the MHC: CD1 and endothelial protein C receptor genes constitute a distinct subfamily of class-I-like genes that predates the emergence of mammals. Immunogenetics 2005; 57:590-600. [PMID: 16133451 DOI: 10.1007/s00251-005-0016-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Accepted: 06/20/2005] [Indexed: 10/25/2022]
Abstract
Mammals have several major histocompatibility complex (MHC) class-I-like genes. Although some of them are assumed to have originated before the emergence of mammals, the origin of class-I-like genes is poorly understood. We analyzed here the recently released chicken draft genome sequence and identified two families of class-I-like genes: CD1 and PROCR (the gene for the endothelial protein C receptor). Chickens have two CD1 genes, designated CD1.1 and CD1.2, located in tandem approximately 840 bp apart from each other. Chicken CD1.1 and CD1.2 are neither group 1- nor group 2-like, indicating that the two groups of CD1 emerged in a mammalian lineage. Although the database provides no information as to their chromosomal localization, we found that chicken CD1 genes are located adjacent to the previously characterized MHC B system contig on chromosome 16. We confirmed the linkage of CD1 to the B system by dual-color fluorescence in situ hybridization. Chickens have a single copy of PROCR. Among known class-I-like genes, PROCR is most closely related to CD1, indicating that CD1 and PROCR constitute a distinct subfamily of class-I-like genes that predates the emergence of mammals.
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Affiliation(s)
- Takako Maruoka
- Department of Pathology, Division of Pathophysiological Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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Hayashi T, Nishioka J, Kamada H, Asanuma K, Kondo H, Gabazza EC, Ido M, Suzuki K. Characterization of a novel human protein C inhibitor (PCI) gene transgenic mouse useful for studying the role of PCI in physiological and pathological conditions. J Thromb Haemost 2004; 2:949-61. [PMID: 15140131 DOI: 10.1111/j.1538-7836.2004.00733.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In humans, protein C inhibitor (PCI) is expressed in various tissues and present in many body fluids including plasma and seminal fluid. In rodents, PCI is expressed in reproductive organs only and is absent in plasma. In this study, we characterized the tissue expression and physiological role of PCI in novel human PCI gene transgenic (TG) mice. Northern blot and immunohistochemical analyses demonstrated that human PCI is expressed in liver hepatocytes, renal epithelial cells as well as heart, brain and reproductive organs of the TG mice. This PCI tissue distribution is similar to that found in humans. PCI in plasma of TG mice showed the same immunological and functional properties as human plasma PCI. Next, we evaluated the effect of PCI on coagulation, inflammation and tissue damage in lipopolysaccharide-treated TG mice. The results suggested that PCI efficiently inhibits not only the anticoagulant and anti-inflammatory activities of exogenously injected human activated protein C (APC) but also that of endogenously produced APC in mice with endotoxemia. These findings suggest that PCI exerts a procoagulant and proinflammatory effect by inhibiting APC. We believe our results also show how useful these TG mice may be for assessing the therapeutic effect of human APC in vivo and for evaluating the role of PCI in human physiological and pathological conditions.
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Affiliation(s)
- T Hayashi
- Department of Molecular Pathobiology, Mie University School of Medicine, Tsu-city, Mie, Japan
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Saposnik B, Reny JL, Gaussem P, Emmerich J, Aiach M, Gandrille S. A haplotype of the EPCR gene is associated with increased plasma levels of sEPCR and is a candidate risk factor for thrombosis. Blood 2003; 103:1311-8. [PMID: 14576048 DOI: 10.1182/blood-2003-07-2520] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The endothelial cell protein C (PC) receptor (EPCR) facilitates PC activation by the thrombin-thrombomodulin complex. A soluble form of this receptor (sEPCR) found in plasma inhibits both activated PC (aPC) activity and PC activation by competing for PC with membrane-associated EPCR. Elevated sEPCR levels are found in approximately 20% of healthy subjects, but the mechanisms underlying this interindividual variability are unknown. We measured sEPCR levels in 100 healthy male volunteers, and observed 2 phenotypic groups of subjects. The temporal stability of sEPCR levels suggested genetic control. Extensive analysis of the EPCR gene in these subjects revealed 13 polymorphisms in complete linkage disequilibrium; these defined 3 haplotypes, 1 of which (A3) was strongly associated with high sEPCR levels. The high constitutive sEPCR levels observed in A3 haplotype carriers might reduce the efficiency of the PC system and predispose these subjects to venous thrombosis. By studying 338 patients with venous thrombosis and 338 age- and sex-matched healthy subjects, we found that the A3 haplotype was overrepresented in the patients. In multivariate analysis, subjects carrying the A3 haplotype had an increased risk of thrombosis (odds ratio [OR] = 1.8; P =.004). Thus, the A3 haplotype, which is associated with elevated plasma sEPCR levels, is a candidate risk factor for venous thrombosis.
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Rance JB, Follows GA, Cockerill PN, Bonifer C, Lane DA, Simmonds RE. Regulation of the human endothelial cell protein C receptor gene promoter by multiple Sp1 binding sites. Blood 2003; 101:4393-401. [PMID: 12560236 DOI: 10.1182/blood-2002-05-1570] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human endothelial cell protein C receptor (hEPCR) is normally expressed by the endothelium of large blood vessels, but the molecular basis for its in vivo specificity is uncertain. In this study, DNaseI hypersensitive site mapping demonstrated the presence of a hypersensitive site in the 5' flanking region of the hEPCR gene in endothelial cells and certain transformed cells (HeLa and U937) known to express hEPCR in vitro. Conversely, this site was only weakly hypersensitive in HepG2 cells, cells which do not express hEPCR mRNA. Functional analysis of this 5' flanking region by in vivo dimethylsulfate footprinting in cultured endothelial cells identified multiple regions, containing high and low homology consensus Sp1 binding sequences, that were protected from methylation in endothelial cells. These sequences were not protected in HepG2 cells. Reporter gene analysis of this region in endothelial cells demonstrated the presence of promoter activity conferred by the proximal 572 bp but failed to identify a functional TATA-box. This promoter was inactive in HepG2 cells. Electrophoresis mobility shift assays using endothelial cell nuclear extracts identified Sp1 family proteins binding to sites that were protected during footprinting. Sp1 sites were identified in regions at -368, -232, -226, -201, -146, and -102 bp relative to the translation start site. With the exception of the site at -102 bp, each identified Sp1 binding site made a positive contribution to reporter gene expression, although no individual site was critically important. We conclude that transcription factor binding to Sp1 binding sites in the 5' flanking region is critical for normal hEPCR gene expression in endothelial cells.
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Affiliation(s)
- James B Rance
- Department of Haematology, Imperial College London-Faculty of Medicine, Hammersmith Hospital Campus, London, United Kingdom.
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Galligan L, Livingstone W, Volkov Y, Hokamp K, Murphy C, Lawler M, Fukudome K, Smith O. Characterization of protein C receptor expression in monocytes. Br J Haematol 2001; 115:408-14. [PMID: 11703343 DOI: 10.1046/j.1365-2141.2001.03187.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Many sequelae associated with endotoxaemic-induced shock result from excessive production of the cytokine mediators, tumour necrosis factor alpha (TNF-alpha), interleukin 1 (IL-1) and IL-6 from lipopolysaccharide (LPS)-activated monocytes. Protein C (PC)/activated protein C (APC) has potent cytokine-modifying properties and is protective in animal models and human clinical trials of sepsis. The precise mechanism by which this anti-inflammatory response is achieved remains unknown; however, the recently described endothelial protein C receptor (EPCR) appears to be essential for this function. The pivotal role that monocytes play in the pathophysiology of septic shock led us to investigate the possible expression of a protein C receptor on the monocyte membrane. We used similarity algorithms to screen human sequence databases for paralogues of the EPCR but found none. However, using reverse transcription-polymerase chain reaction (RT-PCR), we detected an mRNA transcribed in primary human monocytes and THP1 cells that was identical to human EPCR mRNA. We also used immunocytochemical analysis to demonstrate the expression of a protein C receptor on the surface of monocytes encoded by the same gene as EPCR. These results confirm a new member of the protein C pathway involving primary monocytes. Further characterization will be necessary to compare and contrast its biological properties with those of EPCR.
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Affiliation(s)
- L Galligan
- National Centre for Hereditary Coagulation Disorders, St James's Hospital, Dublin, Ireland
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