Activated protein C suppresses osteoclast differentiation via endothelial protein C receptor, protease-activated receptor-1, sphingosine 1-phosphate receptor, and apolipoprotein E receptor 2

2018 ◽  
Vol 163 ◽  
pp. 30-40 ◽  
Author(s):  
Kakunoshin Yoshida ◽  
Nobuyuki Akita ◽  
Takayuki Okamoto ◽  
Kunihiro Asanuma ◽  
Atsumasa Uchida ◽  
...  
Keyword(s):  
Apolipoprotein E ◽  
Protein C ◽  
Osteoclast Differentiation ◽  
Activated Protein C ◽  
Endothelial Protein C Receptor ◽  
Sphingosine 1 Phosphate ◽  
Protease Activated Receptor 1

The structure-function relationship of activated protein C

2011 ◽  
Vol 106 (12) ◽  
pp. 1034-1045. ◽  
Author(s):  
Karin Wildhagen ◽  
Esther Lutgens ◽  
Sarah Loubele ◽  
Hugo ten Cate ◽  
Gerry Nicolaes
Keyword(s):  
Structure Function ◽  
Protein C ◽  
Molecular Mechanisms ◽  
3D Structure ◽  
Activated Protein C ◽  
Protein S ◽  
Coagulation Factors ◽  
Endothelial Protein C Receptor ◽  
Cytoprotective Activity ◽  
Sphingosine 1 Phosphate

SummaryProtein C is the central enzyme of the natural anticoagulant pathway and its activated form APC (activated protein C) is able to proteolyse non-active as well as active coagulation factors V and VIII. Proteolysis renders these cofactors inactive, resulting in an attenuation of thrombin formation and overall down-regulation of coagulation. Presences of the APC cofactor, protein S, thrombomodulin, endothelial protein C receptor and a phospholipid surface are important for the expression of anticoagulant APC activity. Notably, APC also has direct cytoprotective effects on cells: APC is able to protect the endothelial barrier function and expresses anti-inflammatory and anti-apoptotic activities. Exact molecular mechanisms have thus far not been completely described but it has been shown that both the protease activated receptor 1 and EPCR are essential for the cytoprotective activity of APC. Recently it was shown that also other receptors like sphingosine 1 phosphate receptor 1, Cd11b/CD18 and tyrosine kinase with immunoglobulin-like and EGFlike domains 2 are likewise important for APC signalling. Mutagenesis studies are being performed to map the various APC functions and interactions onto its 3D structure and to dissect anticoagulant and cytoprotective properties. The results of these studies have provided a wealth of structure-function information. With this review we describe the state-of-the-art of the intricate structure-function relationships of APC, a protein that harbours several important functions for the maintenance of both humoral and tissue homeostasis.Lessons from natural and engineered mutations

scholarly journals Endothelial Protein C Receptor (EPCR), Protease Activated Receptor-1 (PAR-1) and Their Interplay in Cancer Growth and Metastatic Dissemination

Cancers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 51 ◽  
Author(s):  
Marek Z. Wojtukiewicz ◽  
Dominika Hempel ◽  
Ewa Sierko ◽  
Stephanie C. Tucker ◽  
Kenneth V. Honn
Keyword(s):  
Cell Surface ◽  
Cancer Patients ◽  
Cancer Progression ◽  
Protein C ◽  
Critical Role ◽  
Activated Protein C ◽  
Cancer Growth ◽  
Endothelial Protein C Receptor ◽  
Surface Receptors ◽  
Protease Activated Receptor 1

Endothelial protein C receptor (EPCR) and protease activated receptor 1 (PAR-1) by themselves play important role in cancer growth and dissemination. Moreover, interactions between the two receptors are essential for tumor progression. EPCR is a cell surface transmembrane glycoprotein localized predominantly on endothelial cells (ECs). It is a vital component of the activated protein C (APC)—mediated anticoagulant and cytoprotective signaling cascade. PAR-1, which belongs to a family of G protein–coupled cell surface receptors, is also widely distributed on endothelial and blood cells, where it plays a critical role in hemostasis. Both EPCR and PAR-1, generally considered coagulation-related receptors, are implicated in carcinogenesis and dissemination of diverse tumor types, and their expression correlates with clinical outcome of cancer patients. Existing data explain some mechanisms by which EPCR/PAR-1 affects cancer growth and metastasis; however, the exact molecular basis of cancer invasion associated with the signaling is still obscure. Here, we discuss the role of EPCR and PAR-1 reciprocal interactions in cancer progression as well as potential therapeutic options targeted specifically to interact with EPCR/PAR-1-induced signaling in cancer patients.

scholarly journals Hyperantithrombotic, noncytoprotective Glu149Ala-activated protein C mutant

Blood ◽  
2009 ◽  
Vol 113 (23) ◽  
pp. 5970-5978 ◽  
Author(s):  
Laurent O. Mosnier ◽  
Antonella Zampolli ◽  
Edward J. Kerschen ◽  
Reto A. Schuepbach ◽  
Yajnavalka Banerjee ◽  
...  
Keyword(s):  
Protein C ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Bleeding Risk ◽  
Endothelial Protein C Receptor ◽  
Antithrombotic Activity ◽  
Cytoprotective Activity ◽  
Protease Activated Receptor 1

Abstract Activated protein C (APC) reduces mortality in severe sepsis patients. APC exerts anticoagulant activities via inactivation of factors Va and VIIIa and cytoprotective activities via endothelial protein C receptor and protease-activated receptor-1. APC mutants with selectively altered and opposite activity profiles, that is, greatly reduced anticoagulant activity or greatly reduced cytoprotective activities, are compared here. Glu149Ala-APC exhibited enhanced in vitro anticoagulant and in vivo antithrombotic activity, but greatly diminished in vitro cytoprotective effects and in vivo reduction of endotoxin-induced murine mortality. Thus, residue Glu149 and the C-terminal region of APC's light chain are identified as functionally important for expression of multiple APC activities. In contrast to Glu149Ala-APC, 5A-APC (Lys191-193Ala + Arg229/230Ala) with protease domain mutations lacked in vivo antithrombotic activity, although it was potent in reducing endotoxin-induced mortality, as previously shown. These data imply that APC molecular species with potent antithrombotic activity, but without robust cytoprotective activity, are not sufficient to reduce mortality in endotoxemia, emphasizing the need for APC's cytoprotective actions, but not anticoagulant actions, to reduce endotoxin-induced mortality. Protein engineering can provide APC mutants that permit definitive mechanism of action studies for APC's multiple activities, and may also provide safer and more effective second-generation APC mutants with reduced bleeding risk.

scholarly journals The ligand occupancy of endothelial protein C receptor switches the protease-activated receptor 1-dependent signaling specificity of thrombin from a permeability-enhancing to a barrier-protective response in endothelial cells

Blood ◽  
2007 ◽  
Vol 110 (12) ◽  
pp. 3909-3916 ◽  
Author(s):  
Jong-Sup Bae ◽  
Likui Yang ◽  
Chandrashekhara Manithody ◽  
Alireza R. Rezaie
Keyword(s):  
Endothelial Cells ◽  
Protein C ◽  
Vascular Endothelial Cells ◽  
Activated Protein C ◽  
Catalytic Efficiency ◽  
Endothelial Protein C Receptor ◽  
New Paradigm ◽  
Caveolin 1 ◽  
Protease Activated Receptor 1 ◽  
Protective Signaling

AbstractRecent studies have indicated that activated protein C (APC) may exert its cytoprotective and anti-inflammatory activities through the endothelial protein C receptor (EPCR)-dependent cleavage of protease-activated receptor 1 (PAR-1) on vascular endothelial cells. Noting that (1) the activation of protein C on endothelial cells requires thrombin, (2) relative to APC, thrombin cleaves PAR-1 with approximately 3 to 4 orders of magnitude higher catalytic efficiency, and (3) PAR-1 is a target for the proinflammatory activity of thrombin, it is not understood how APC can elicit a protective signaling response through the cleavage of PAR-1 when thrombin is present. In this study, we demonstrate that EPCR is associated with caveolin-1 in lipid rafts of endothelial cells and that its occupancy by the γ-carboxyglutamic acid (Gla) domain of protein C/APC leads to its dissociation from caveolin-1 and recruitment of PAR-1 to a protective signaling pathway through coupling of PAR-1 to the pertussis toxin–sensitive Gi-protein. Thus, when EPCR is bound by protein C, the PAR-1 cleavage-dependent protective signaling responses in endothelial cells can be mediated by either thrombin or APC. These results provide a new paradigm for understanding how PAR-1 and EPCR participate in protective signaling events in endothelial cells.

scholarly journals Testing the effect of PAR1 inhibitors on Plasmodium falciparum-induced loss of endothelial cell barrier function

2020 ◽  
Vol 5 ◽  
pp. 34
Author(s):  
Janet Storm ◽  
Yang Wu ◽  
Jill Davies ◽  
Christopher A. Moxon ◽  
Alister G. Craig
Keyword(s):  
Endothelial Cells ◽  
Plasmodium Falciparum ◽  
Cerebral Malaria ◽  
Barrier Function ◽  
Protein C ◽  
Activated Protein C ◽  
Endothelial Activation ◽  
Endothelial Protein C Receptor ◽  
Microvascular Endothelium ◽  
Protease Activated Receptor 1

Background: Sequestration and cytoadherence of Plasmodium falciparum-infected erythrocytes (IE) to microvascular endothelium alters endothelial barrier function and plays a role in the pathogenesis of severe malaria. Binding of IE is mediated by P. falciparum erythrocyte membrane protein 1 (PfEMP1) and the PfEMP1 variants that binds to endothelial protein C receptor (EPCR) have, in particular, been associated with the dysregulation of the coagulation/inflammation pathways in endothelial cells. This has prompted speculation about the role of protease-activated receptor-1 (PAR1) activation and signalling in causing endothelial activation and loss of barrier function in cerebral malaria. Methods: We used a co-culture of primary human brain microvascular endothelial cells (HBMEC) with P. falciparum material, recombinant PfEMP1 or lysates from IE, and measured barrier function by trans endothelial electrical resistance (TEER).  A selection of PAR1 inhibitors was tested for their ability to reverse the P. falciparum and thrombin induced decrease in barrier function. Results: An initial screen in the presence of recombinant PfEMP1 identified a few inhibitors that were able to reduce the rapid thrombin-induced barrier disruption even when activated protein C (aPC) was unable to do so. However, in the IE lysate co-culture system we identified a mechanism that slowly reduces barrier function and which is insensitive to PAR1 inhibitors. Conclusions: The selected PAR1 inhibitors were able to reverse the disruption of barrier function by thrombin but did not reverse the IE lysate induced disruption of barrier function, implicating a different PAR1-independent mechanism.  These findings have implications for the design of adjunct therapies to reduce brain swelling in cerebral malaria.

Endothelial protein C receptor–expressing hematopoietic stem cells reside in the perisinusoidal niche in fetal liver

Blood ◽  
2010 ◽  
Vol 116 (4) ◽  
pp. 544-553 ◽  
Author(s):  
Hiroko Iwasaki ◽  
Fumio Arai ◽  
Yoshiaki Kubota ◽  
Maria Dahl ◽  
Toshio Suda
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Protein C ◽  
Fetal Liver ◽  
Activated Protein C ◽  
Endothelial Protein C Receptor ◽  
Hematopoietic Stem ◽  
Protease Activated Receptor 1 ◽  
Slow Cycling

Abstract Hematopoietic stem cells (HSCs) are maintained in specialized niches in adult bone marrow. However, niche and HSC maintenance mechanism in fetal liver (FL) still remains unclear. Here, we investigated the niche and the molecular mechanism of HSC maintenance in mouse FL using HSCs expressing endothelial protein C receptor (EPCR). The antiapoptotic effect of activated protein C (APC) on EPCR+ HSCs and the expression of protease-activated receptor 1 (Par-1) mRNA in these cells suggested the involvement of the cytoprotective APC/EPCR/Par-1 pathway in HSC maintenance. Immunohistochemistry revealed that EPCR+ cells were localized adjacent to, or integrated in, the Lyve-1+ sinusoidal network, where APC and extracellular matrix (ECM) are abundant, suggesting that HSCs in FL were maintained in the APC- and ECM-rich perisinusoidal niche. EPCR+ HSCs were in a relatively slow cycling state, consistent with their high expression levels of p57 and p18. Furthermore, the long-term reconstitution activity of EPCR+ HSCs decreased significantly after short culture but not when cocultured with feeder layer of FL-derived Lyve-1+ cells, which suggests that the maintenance of the self-renewal activity of FL HSCs largely depended on the interaction with the perisinusoidal niche. In conclusion, EPCR+ HSCs resided in the perisinusoidal niche in mouse FL.

scholarly journals Cytoprotective signaling by activated protein C requires protease-activated receptor-3 in podocytes

Blood ◽  
2012 ◽  
Vol 119 (3) ◽  
pp. 874-883 ◽  
Author(s):  
Thati Madhusudhan ◽  
Hongjie Wang ◽  
Beate K. Straub ◽  
Elisabeth Gröne ◽  
Qianxing Zhou ◽  
...  
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Cell Types ◽  
Endothelial Protein C Receptor ◽  
Signaling Mechanism ◽  
Proteolytic Activation ◽  
Caveolin 1 ◽  
Cell Type Specific ◽  
Protease Activated Receptor 1

Abstract The cytoprotective effects of activated protein C (aPC) are well established. In contrast, the receptors and signaling mechanism through which aPC conveys cytoprotection in various cell types remain incompletely defined. Thus, within the renal glomeruli, aPC preserves endothelial cells via a protease-activated receptor-1 (PAR-1) and endothelial protein C receptor-dependent mechanism. Conversely, the signaling mechanism through which aPC protects podocytes remains unknown. While exploring the latter, we identified a novel aPC/PAR-dependent cytoprotective signaling mechanism. In podocytes, aPC inhibits apoptosis through proteolytic activation of PAR-3 independent of endothelial protein C receptor. PAR-3 is not signaling competent itself as it requires aPCinduced heterodimerization with PAR-2 (human podocytes) or PAR-1 (mouse podocytes). This cytoprotective signaling mechanism depends on caveolin-1 dephosphorylation. In vivo aPC protects against lipopolysaccharide-induced podocyte injury and proteinuria. Genetic deletion of PAR-3 impairs the nephroprotective effect of aPC, demonstrating the crucial role of PAR-3 for aPC-dependent podocyte protection. This novel, aPC-mediated interaction of PARs demonstrates the plasticity and cell-specificity of cytoprotective aPC signaling. The evidence of specific, dynamic signaling complexes underlying aPC-mediated cytoprotection may allow the design of cell type specific targeted therapies.

scholarly journals aPC/PAR1 confers endothelial anti-apoptotic activity via a discrete β-arrestin-2 mediated SphK1-S1PR1-Akt signaling axis

2021 ◽  
Author(s):  
Olivia Molinar-Inglis ◽  
Cierra A. Birch ◽  
Dequina Nicholas ◽  
Metzli Cisneros-Aguirre ◽  
Anand Patwardhan ◽  
...  
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Vascular Diseases ◽  
Akt Signaling ◽  
Sphingosine Kinase 1 ◽  
Caveolin 1 ◽  
Signaling Axis ◽  
Sphingosine 1 Phosphate ◽  
Protease Activated Receptor 1 ◽  
Apoptotic Activity

Endothelial dysfunction is associated with multiple vascular diseases and lacks effective treatments. Activated Protein C (aPC) is a promising biotherapeutic that signals via protease-activated receptor-1 (PAR1) to promote diverse cytoprotective responses, including endothelial barrier stabilization, anti-inflammatory and anti-apoptotic activities, which is facilitated by co-receptors. We showed that aPC-activated PAR1 signals preferentially via b-arrestin-2 (b-arr2) and dishevelled-2 (Dvl2) scaffolds rather than G proteins to enhance barrier protection. However, the mechanisms by which aPC/PAR1 promotes other cytoprotective responses are poorly understood. Here we define a novel β-arr2-mediated sphingosine kinase-1 (SphK1)-sphingosine-1-phosphate receptor-1 (S1PR1)-Akt signaling axis that confers aPC/PAR1-mediated protection against cell death. We show that PAR1 and S1PR1 co-exist in caveolin-1-rich microdomains basally and aPC markedly increases S1PR1-caveolin-1 co-association. Moreover, aPC stimulates b-arr2-dependent SphK1 activation independent of Dvl2, which is critical for S1PR1 transactivation. These studies reveal that different aPC/PAR1 cytoprotective responses are mediated by discrete b-arr2-driven signaling pathways in caveolae.

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