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.

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

2021 ◽  
Vol 118 (49) ◽  
pp. e2106623118
Author(s):  
Olivia Molinar-Inglis ◽  
Cierra A. Birch ◽  
Dequina Nicholas ◽  
Lennis Orduña-Castillo ◽  
Metztli Cisneros-Aguirre ◽  
...  
Keyword(s):  
Cell Death ◽  
Endothelial Dysfunction ◽  
Signaling Pathways ◽  
Activated Protein C ◽  
Akt Signaling ◽  
Endothelial Barrier ◽  
Structural Protein ◽  
Signaling Axis ◽  
Sphingosine 1 Phosphate ◽  
Apoptotic Activity

Endothelial dysfunction is associated with vascular disease and results in disruption of endothelial barrier function and increased sensitivity to apoptosis. Currently, there are limited treatments for improving endothelial dysfunction. Activated protein C (aPC), a promising therapeutic, signals via protease-activated receptor-1 (PAR1) and mediates several cytoprotective responses, including endothelial barrier stabilization and anti-apoptotic responses. We showed that aPC-activated PAR1 signals preferentially via β-arrestin-2 (β-arr2) and dishevelled-2 (Dvl2) scaffolds rather than G proteins to promote Rac1 activation and barrier protection. However, the signaling pathways utilized by aPC/PAR1 to mediate anti-apoptotic activities are not known. aPC/PAR1 cytoprotective responses also require coreceptors; however, it is not clear how coreceptors impact different aPC/PAR1 signaling pathways to drive distinct cytoprotective responses. Here, we define a 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. Using human cultured endothelial cells, we found that endogenous PAR1 and S1PR1 coexist in caveolin-1 (Cav1)–rich microdomains and that S1PR1 coassociation with Cav1 is increased by aPC activation of PAR1. Our study further shows that aPC stimulates β-arr2–dependent SphK1 activation independent of Dvl2 and is required for transactivation of S1PR1-Akt signaling and protection against cell death. While aPC/PAR1-induced, extracellular signal–regulated kinase 1/2 (ERK1/2) activation is also dependent on β-arr2, neither SphK1 nor S1PR1 are integrated into the ERK1/2 pathway. Finally, aPC activation of PAR1-β-arr2–mediated protection against apoptosis is dependent on Cav1, the principal structural protein of endothelial caveolae. These studies reveal that different aPC/PAR1 cytoprotective responses are mediated by discrete, β-arr2–driven signaling pathways in caveolae.

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 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 Inhibition of staurosporine-induced apoptosis of endothelial cells by activated protein C requires protease-activated receptor-1 and endothelial cell protein C receptor

2003 ◽  
Vol 373 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Laurent O. MOSNIER ◽  
John H. GRIFFIN
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Active Site ◽  
Protein C ◽  
Activated Protein C ◽  
Cell Protein ◽  
Protease Activated Receptor 1 ◽  
Induced Apoptosis ◽  
Apoptotic Effects ◽  
Dose Dependent

In a model of staurosporine-induced apoptosis using EAhy926 endothelial cells, inhibition of apoptosis by activated protein C was dose-dependent and required the enzyme's active site, implicating activated protein C-mediated proteolysis. Consistent with this implication, both protease-activated receptor-1 (PAR-1) and endothelial cell protein C receptor (EPCR) were required for the anti-apoptotic effects of activated protein C.

Protection of ischemic white matter and oligodendrocytes in mice by 3K3A-activated protein C

2021 ◽  
Vol 219 (1) ◽  
Author(s):  
Mikko T. Huuskonen ◽  
Yaoming Wang ◽  
Angeliki Maria Nikolakopoulou ◽  
Axel Montagne ◽  
Zhonghua Dai ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
White Matter ◽  
Corpus Callosum ◽  
Functional Outcomes ◽  
Protein C ◽  
Activated Protein C ◽  
Clinical Importance ◽  
Subcortical White Matter ◽  
Stroke Patients ◽  
Protease Activated Receptor 1

Subcortical white matter (WM) stroke accounts for 25% of all strokes and is the second leading cause of dementia. Despite such clinical importance, we still do not have an effective treatment for ischemic WM stroke, and the mechanisms of WM postischemic neuroprotection remain elusive. 3K3A-activated protein C (APC) is a signaling-selective analogue of endogenous blood protease APC that is currently in development as a neuroprotectant for ischemic stroke patients. Here, we show that 3K3A-APC protects WM tracts and oligodendrocytes from ischemic injury in the corpus callosum in middle-aged mice by activating protease-activated receptor 1 (PAR1) and PAR3. We show that PAR1 and PAR3 were also required for 3K3A-APC’s suppression of post–WM stroke microglia and astrocyte responses and overall improvement in neuropathologic and functional outcomes. Our data provide new insights into the neuroprotective APC pathway in the WM and illustrate 3K3A-APC’s potential for treating WM stroke in humans, possibly including multiple WM strokes that result in vascular dementia.

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 Sphingosine Kinase 1 Signaling in Breast Cancer: A Potential Target to Tackle Breast Cancer Stem Cells

2021 ◽  
Vol 8 ◽  
Author(s):  
Ling-Wei Hii ◽  
Felicia Fei-Lei Chung ◽  
Chun-Wai Mai ◽  
Pei Yuen Ng ◽  
Chee-Onn Leong
Keyword(s):  
Breast Cancer ◽  
Stem Cells ◽  
Cancer Stem Cells ◽  
Cancer Cells ◽  
Sphingosine Kinase ◽  
Sphingosine Kinase 1 ◽  
Signaling Axis ◽  
Sphingosine 1 Phosphate ◽  
Sphingosine Kinases ◽  
Research Findings

Sphingosine kinases (SPHKs) are conserved lipid enzymes that catalyze the formation of sphingosine-1-phosphate (S1P) through ATP-dependent phosphorylation of sphingosine. Two distinct SPHK isoforms, namely SPHK1 and SPHK2, have been identified to date, and the former has been implicated for its oncogenic roles in cancer development and progression. While SPHK1 signaling axis has been extensively studied in non-stem breast cancer cells, recent evidence has emerged to suggest a role of SPHK1 in regulating cancer stem cells (CSCs). With the clinical implications of CSCs in disease relapse and metastasis, it is believed that therapeutic approaches that can eradicate both non-stem cancer cells and CSCs could be a key to cancer cure. In this review, we first explore the oncogenic functions of sphingosine kinase 1 in human cancers and summarize current research findings of SPHK1 signaling with a focus on breast cancer. We also discuss the therapeutic potentials and perspectives of targeting SPHK1 signaling in breast cancer and cancer stem cells. We aim to offer new insights and inspire future studies looking further into the regulatory functions of SPHK1 in CSC-driven tumorigenesis, uncovering novel therapeutic avenues of using SPHK1-targeted therapy in the treatment of CSC-enriched refractory cancers.

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