The endothelial protein C receptor impairs the antibacterial response in murine pneumococcal pneumonia and sepsis

2014 ◽  
Vol 111 (05) ◽  
pp. 970-980 ◽  
Author(s):  
J. Daan de Boer ◽  
Liesbeth M. Kager ◽  
Joris J. T. H. Roelofs ◽  
Joost C. M. Meijers ◽  
Charles T. Esmon ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Bacterial Growth ◽  
Protein C ◽  
Pneumococcal Pneumonia ◽  
Wild Type ◽  
Endothelial Protein C Receptor ◽  
Pulmonary Endothelium ◽  
Pneumococcal Sepsis ◽  
Bacterial Outgrowth

SummaryPneumococcal pneumonia is a frequent cause of gram-positive sepsis and has a high mortality. The endothelial protein C receptor (EPCR) has been implicated in both the activation of protein C (PC) and the anti-inflammatory actions of activated (A)PC. The aim of this study was to determine the role of the EPCR in murine pneumococcal pneumonia and sepsis. Wild-type (WT), EPCR knockout (KO) and Tie2-EPCR mice, which overexpress EPCR on the endothelium, were infected intranasally (pneumonia) or intravenously (sepsis) with viable Streptococcus pneumoniae and euthanised at 24 or 48 hours after initiation of the infection for analyses. Pneumonia did not alter constitutive EPCR expression on pulmonary endothelium but was associated with an influx of EPCR positive neutrophils into lung tissue. In pneumococcal pneumonia EPCR KO mice demonstrated diminished bacterial growth in the lungs and dissemination to spleen and liver, reduced neutrophil recruitment to the lungs and a mitigated inflammatory response. Moreover, EPCR KO mice displayed enhanced activation of coagulation in the early phase of disease. Correspondingly, in pneumococcal sepsis EPCR KO mice showed reduced bacterial growth in lung and liver and attenuated cytokine release. Conversely, EPCR-overexpressing mice displayed higher bacterial outgrowth in lung, blood, spleen and liver in pneumococcal sepsis. In conclusion, EPCR impairs antibacterial defense in both pneumococcal pneumonia and sepsis, which is associated with an enhanced pro-inflammatory response.

scholarly journals The Contribution of PspC to Pneumococcal Virulence Varies between Strains and Is Accomplished by Both Complement Evasion and Complement-Independent Mechanisms

2006 ◽  
Vol 74 (9) ◽  
pp. 5319-5324 ◽  
Author(s):  
Alison R. Kerr ◽  
Gavin K. Paterson ◽  
Jackie McCluskey ◽  
Francesco Iannelli ◽  
Marco R. Oggioni ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Protein C ◽  
Pneumococcal Pneumonia ◽  
Surface Protein ◽  
Murine Models ◽  
Wild Type ◽  
Survival Times ◽  
Pneumococcal Strain ◽  
Wild Type Parent

ABSTRACTPneumococcal surface protein C (PspC) is a virulence factor ofStreptococcus pneumoniaepreviously shown to play a role in bacterial adherence, invasion, and evasion of complement. We investigated the role of this protein in our murine models of pneumococcal pneumonia with different pneumococcal strains. The deletion ofpspCin strains of serotypes 2, 3, and 19F did not significantly alter host survival times in the pneumonia model. In contrast,pspCdeletion significantly reduced the virulence of the serotype 4 strain, TIGR4, in both the pneumonia and bacteremia models. Therefore,pspCis a systemic and pulmonary virulence determinant forS. pneumoniae, but its effects are influenced by the pneumococcal strain. Finally, pneumonia infection of complement-deficient (C3−/−) mice enhancedpspCvirulence, illustrating that PspC-mediated complement evasion contributes to virulence. However, other functions of PspC also contribute to virulence, as demonstrated by the finding that thepspC-deficient TIGR4 mutant was still attenuated relative to the wild-type parent, even in the absence of C3.

scholarly journals Activation of endothelial intrinsic NF-κB pathway impairs protein C anticoagulation mechanism and promotes coagulation in endotoxemic mice

Blood ◽  
2009 ◽  
Vol 114 (12) ◽  
pp. 2521-2529 ◽  
Author(s):  
Dongmei Song ◽  
Xiaobing Ye ◽  
Honglei Xu ◽  
Shu Fang Liu
Keyword(s):  
Transgenic Mice ◽  
Tissue Factor ◽  
Protein C ◽  
Nuclear Factor Κb ◽  
Tissue Factor Expression ◽  
Wild Type ◽  
Endothelial Protein C Receptor ◽  
Lps Challenge ◽  
Factor Expression

Abstract Although the role of systemic activation of the nuclear factor κB (NF-κB) pathway in septic coagulation has been well documented, little is known about the contribution of endothelial-specific NF-κB signaling in this pathologic process. Here, we used transgenic mice that conditionally overexpress a mutant I-κBα, an inhibitor of NF-κB, selectively on endothelium, and their wild-type littermates to define the role of endothelial-specific NF-κB in septic coagulation. In wild-type mice, lipopolysaccharide (LPS) challenge (5 mg/kg intraperitoneally) caused markedly increased plasma markers of coagulation, decreased plasma fibrinogen level, and widespread tissue fibrin deposition, which were abrogated by endothelial NF-κB blockade in transgenic mice. Endothelial NF-κB blockade inhibited tissue factor expression in endothelial cells, but not in leukocytes. Endothelial NF-κB blockade did not inhibit LPS-induced tissue factor expression in heart, kidney, and liver. Endothelial NF-κB blockade prevented LPS down-regulation of endothelial protein C receptor (EPCR) and thrombomodulin protein expressions, inhibited tissue tumor necrosis factor-α converting enzyme activity, reduced EPCR shedding, and restored plasma protein C level. Our data demonstrate that endothelial intrinsic NF-κB signaling plays a pivotal role in septic coagulation and suggests a link between endothelial-specific NF-κB activation and the impairment of the thrombomodulin-protein C-EPCR anticoagulation pathway.

scholarly journals A thrombomodulin mutation that impairs activated protein C generation results in uncontrolled lung inflammation during murine tuberculosis

Blood ◽  
2005 ◽  
Vol 106 (8) ◽  
pp. 2761-2768 ◽  
Author(s):  
Sebastiaan Weijer ◽  
Catharina W. Wieland ◽  
Sandrine Florquin ◽  
Tom van der Poll
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Inflammatory Response ◽  
Lung Inflammation ◽  
Protein C ◽  
Essential Role ◽  
Activated Protein C ◽  
Wild Type ◽  
Anti Inflammatory

AbstractThrombomodulin (TM) plays an essential role in the generation of activated protein C (APC), a mediator with both anticoagulant and anti-inflammatory properties, and is preferentially expressed in lungs. To investigate the role of TM in the coagulant and inflammatory response in the lung during tuberculosis, mice with a mutation in the TM gene (Thbd), which results in a minimal capacity for APC generation (TMpro/pro mice), were intranasally infected with live virulent Mycobacterium tuberculosis. Whereas pulmonary tuberculosis was not associated with activation of coagulation in either wild-type or TMpro/pro mice, 5 weeks after infection TMpro/pro mice displayed an uncontrolled inflammatory response in their lungs, as reflected by higher lung weights, a diminished ability to form well-shaped granulomas, elevated levels of proinflammatory cytokines, and concurrently reduced concentrations of anti-inflammatory cytokines. During a 36-week follow-up after infection with a lower dose of M tuberculosis, 35% of TMpro/pro mice died from week 28 onward versus none of the wild-type mice, and the surviving TMpro/pro mice displayed increased lung inflammation accompanied by higher mycobacterial loads in liver and spleen. These data suggest that a TM mutation that impairs APC generation results in uncontrolled lung inflammation during tuberculosis.

Activated Protein C Strengthens Cardiac Tolerance to Ischemic Insults in Aging

2021 ◽  
Author(s):  
Di Ren ◽  
Julia Fedorova ◽  
Kayla Davitt ◽  
Tran Ngoc Van Le ◽  
John H Griffin ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein C ◽  
Ex Vivo ◽  
Activated Protein C ◽  
Wild Type ◽  
Endothelial Protein C Receptor ◽  
Cardiac Damage ◽  
Downstream Signaling ◽  
Cardioprotective Effects ◽  
Epcr Shedding

Background: Activated protein C (APC) is a plasma serine protease with anticoagulant and anti-inflammatory activities. Endothelial protein C receptor (EPCR) is associated with APC's activity and mediates its downstream signaling events. APC exerts cardioprotective effects during ischemia and reperfusion (I/R). This study aims to characterize the role of the APC-EPCR axis in ischemic insults in aging. Methods: Young (3-4 months) and aged (24-26 months) wild type C57BL/6J mice, as well as EPCR point mutation (EPCR R84A/R84A ) knock-in C57BL/6J mice incapable of interaction with APC and its wild type of littermate C57BL/6J mice, were subjected to I/R. Wild type APC, signaling-selective APC-2Cys, or anticoagulant-selective APC-E170A were administrated before reperfusion. Results: The results demonstrated that cardiac I/R reduces APC activity, and the APC activity was impaired in the aged versus young hearts possibly attributable to the declined EPCR level with aging. Serum EPCR measurement showed that I/R triggered the shedding of membrane EPCR into circulation, while administration of APC attenuated the I/R-induced EPCR shedding in both young and aged hearts. Subsequent echocardiography showed that APC and APC-2Cys but not APC-E170A ameliorated cardiac dysfunction during I/R in both young and aged mice. Importantly, APC elevated the resistance of the aged heart to ischemic insults through stabilizing EPCR. However, all these cardioprotective effects of APC were blunted in the EPCR R84A/R84A mice versus its wild-type littermates. The ex vivo working heart and metabolomics results demonstrated that AMP-activated protein kinase (AMPK) mediates acute adaptive response while protein kinase B (AKT) is involved in chronic metabolic programming in the hearts with APC treatment. Conclusions: I/R stress causes shedding of the membrane EPCR in the heart, and administration of APC prevents I/R-induced cardiac EPCR shedding that is critical for limiting cardiac damage in aging.

scholarly journals Pneumococcal Surface Protein C Contributes to Sepsis Caused by Streptococcus pneumoniae in Mice

2004 ◽  
Vol 72 (5) ◽  
pp. 3077-3080 ◽  
Author(s):  
Francesco Iannelli ◽  
Damiana Chiavolini ◽  
Susanna Ricci ◽  
Marco Rinaldo Oggioni ◽  
Gianni Pozzi
Keyword(s):  
Streptococcus Pneumoniae ◽  
Protein C ◽  
Lethal Dose ◽  
Surface Protein ◽  
Infection Model ◽  
Wild Type ◽  
Mutant Strains ◽  
Type 3

ABSTRACT The role of pneumococcal surface protein C (PspC; also called SpsA, CbpA, and Hic) in sepsis by Streptococcus pneumoniae was investigated in a murine infection model. The pspC gene was deleted in strains D39 (type 2) and A66 (type 3), and the mutants were tested by being injected intravenously into mice. The animals infected with the mutant strains showed a significant increase in survival, with the 50% lethal dose up to 250-fold higher than that for the wild type. Our findings indicate that PspC affords a decisive contribution to sepsis development.

scholarly journals Activated protein C protects against ventilator-induced pulmonary capillary leak

2009 ◽  
Vol 296 (6) ◽  
pp. L1002-L1011 ◽  
Author(s):  
James H. Finigan ◽  
Adel Boueiz ◽  
Emily Wilkinson ◽  
Rachel Damico ◽  
Jarrett Skirball ◽  
...  
Keyword(s):  
Lung Injury ◽  
Protein C ◽  
Activated Protein C ◽  
Coagulation System ◽  
Blue Dye ◽  
Specific Gene ◽  
Capillary Leakage ◽  
Endothelial Protein C Receptor ◽  
Pulmonary Endothelium ◽  
Pulmonary Capillary

The coagulation system is central to the pathophysiology of acute lung injury. We have previously demonstrated that the anticoagulant activated protein C (APC) prevents increased endothelial permeability in response to edemagenic agonists in endothelial cells and that this protection is dependent on the endothelial protein C receptor (EPCR). We currently investigate the effect of APC in a mouse model of ventilator-induced lung injury (VILI). C57BL/6J mice received spontaneous ventilation (control) or mechanical ventilation (MV) with high (HVT; 20 ml/kg) or low (LVT; 7 ml/kg) tidal volumes for 2 h and were pretreated with APC or vehicle via jugular vein 1 h before MV. In separate experiments, mice were ventilated for 4 h and received APC 30 and 150 min after starting MV. Indices of capillary leakage included bronchoalveolar lavage (BAL) total protein and Evans blue dye (EBD) assay. Changes in pulmonary EPCR protein and Rho-associated kinase (ROCK) were assessed using SDS-PAGE. Thrombin generation was measured via plasma thrombin-antithrombin complexes. HVT induced pulmonary capillary leakage, as evidenced by significant increases in BAL protein and EBD extravasation, without significantly increasing thrombin production. HVT also caused significant decreases in pulmonary, membrane-bound EPCR protein levels and increases in pulmonary ROCK-1. APC treatment significantly decreased pulmonary leakage induced by MV when given either before or after initiation of MV. Protection from capillary leakage was associated with restoration of EPCR protein expression and attenuation of ROCK-1 expression. In addition, mice overexpressing EPCR on the pulmonary endothelium were protected from HVT-mediated injury. Finally, gene microarray analysis demonstrated that APC significantly altered the expression of genes relevant to vascular permeability at the ontology (e.g., blood vessel development) and specific gene (e.g., MAPK-associated kinase 2 and integrin-β6) levels. These findings indicate that APC is barrier-protective in VILI and that EPCR is a critical participant in APC-mediated protection.

scholarly journals CCL3 contributes to secondary damage after spinal cord injury

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Nicolas Pelisch ◽  
Jose Rosas Almanza ◽  
Kyle E. Stehlik ◽  
Brandy V. Aperi ◽  
Antje Kroner
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Inflammatory Response ◽  
Lesion Size ◽  
Secondary Injury ◽  
Wild Type ◽  
Locomotor Recovery ◽  
Secondary Damage ◽  
Cord Injury

Abstract Background Secondary damage after spinal cord injury (SCI) is characterized by a cascade of events including hemorrhage, apoptosis, oxidative stress, and inflammation which increase the lesion size which can influence the functional impairment. Thus, identifying specific mechanisms attributed to secondary injury is critical in minimizing tissue damage and improving neurological outcome. In this work, we are investigating the role of CCL3 (macrophage inflammatory protein 1-α, MIP-1α), a chemokine involved in the recruitment of inflammatory cells, which plays an important role in inflammatory conditions of the central and peripheral nervous system. Methods A mouse model of lower thoracic (T11) spinal cord contusion injury was used. We assessed expression levels of CCL3 and its receptors on the mRNA and protein level and analyzed changes in locomotor recovery and the inflammatory response in the injured spinal cord of wild-type and CCL3−/− mice. Results The expression of CCL3 and its receptors was increased after thoracic contusion SCI in mice. We then examined the role of CCL3 after SCI and its direct influence on the inflammatory response, locomotor recovery and lesion size using CCL3−/− mice. CCL3−/− mice showed mild but significant improvement of locomotor recovery, a smaller lesion size and reduced neuronal damage compared to wild-type controls. In addition, neutrophil numbers as well as the pro-inflammatory cytokines and chemokines, known to play a deleterious role after SCI, were markedly reduced in the absence of CCL3. Conclusion We have identified CCL3 as a potential target to modulate the inflammatory response and secondary damage after SCI. Collectively, this study shows that CCL3 contributes to progressive tissue damage and functional impairment during secondary injury after SCI.

Exploring the role of the phospholipid ligand in endothelial protein C receptor: A molecular dynamics study

2010 ◽  
Vol 78 (12) ◽  
pp. 2679-2690 ◽  
Author(s):  
Federica Chiappori ◽  
Ivan Merelli ◽  
Luciano Milanesi ◽  
Ermanna Rovida
Keyword(s):  
Molecular Dynamics ◽  
Protein C ◽  
Endothelial Protein C Receptor

scholarly journals Role of Pneumococcal Surface Protein C in Nasopharyngeal Carriage and Pneumonia and Its Ability To Elicit Protection against Carriage of Streptococcus pneumoniae

2002 ◽  
Vol 70 (5) ◽  
pp. 2526-2534 ◽  
Author(s):  
Priya Balachandran ◽  
Alexis Brooks-Walter ◽  
Anni Virolainen-Julkunen ◽  
Susan K. Hollingshead ◽  
David E. Briles
Keyword(s):  
Streptococcus Pneumoniae ◽  
Protein C ◽  
Surface Protein ◽  
Wild Type ◽  
Nasal Tissue ◽  
Cholera Toxin Subunit B ◽  
Colonization Model ◽  
Subunit B

ABSTRACT Previous studies suggested that PspC is important in adherence and colonization within the nasopharynx. In this study, we conducted mutational studies to further identify the role PspC plays in the pathogenesis of pneumococci. pspC and/or pspA was insertionally inactivated in a serotype 2 Streptococcus pneumoniae strain and in a serotype 19 S. pneumoniae strain. In the mouse colonization model, pneumococcal strains with mutations in pspC were significantly attenuated in their abilities to colonize. In a mouse pneumonia model, strains with mutations in pspC were unable to infect or multiply within the lung. Using reverse transcriptase PCR we were able to demonstrate that pspC is actively transcribed in vivo, when the bacteria are growing in the nasal cavity and in the lungs. In the bacteremia model, a strain mutated for pspC alone behaved like the wild type, but the absence of both pspC and pspA caused accelerated clearance of the bacteria. Intranasal immunization with PspC with cholera toxin subunit B as an adjuvant protected against intranasal challenge. Evidence was also obtained that revertants that spontaneously acquired PspC expression could multiply and colonize the nasal tissue. This latter finding strongly indicates that pneumococci are actively metabolizing and growing while in the nasopharynx.

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