scholarly journals Rickettsia rickettsii infection of cultured endothelial cells induces release of large von Willebrand factor multimers from Weibel-Palade bodies

Blood ◽  
1991 ◽  
Vol 78 (10) ◽  
pp. 2595-2602 ◽  
Author(s):  
LA Sporn ◽  
RJ Shi ◽  
SO Lawrence ◽  
DJ Silverman ◽  
VJ Marder

Abstract The clinical manifestations of Rocky Mountain spotted fever (RMSF) result from Rickettsia rickettsii (R rickettsii) infection of endothelial cells and are mediated by pathologic changes localized to the vessel, including in situ thrombosis and tissue ischemia. This study uses in vitro infection of cultured human umbilical vein endothelial cells with R rickettsii to test the hypothesis that such infection induces von Willebrand factor (vWF) release from Weibel- Palade bodies, a process that could contribute to thrombotic changes. At 24 hours postinfection, there was an increase in metabolically prelabeled large multimers of vWF in the culture medium, with a concomitant decrease of these forms in the cell lysate samples. This release reaction was specific for the large multimer pool of vWF, localized to Weibel-Palade bodies, because no change in the distribution of dimeric forms between cells and culture medium was detected. Double-label immunofluorescence staining showed an inverse correlation between the number of R rickettsii and the number of Weibel- Palade bodies in infected cells. Cell lysis was minimal at 24 hours postinfection, as no detectable intracellular precursor forms (molecular weight 260,000) of vWF were released into the culture medium, there was no decrease in cell viability as measured by trypan blue exclusion, and no increase in 51Cr-release into the culture medium was observed when compared with uninfected controls. Release was likely a direct effect of the intracellular presence of the organism, rather than due to a noxious soluble factor such as endotoxin, because culture medium conditioned by infected endothelial cells was ineffective at inducing release in uninfected endothelial cell cultures. In summary, in vitro infection of endothelial cells by R rickettsii induces release of Weibel-Palade body contents, a process that may contribute to the pathogenesis of RMSF.

Blood ◽  
1991 ◽  
Vol 78 (10) ◽  
pp. 2595-2602
Author(s):  
LA Sporn ◽  
RJ Shi ◽  
SO Lawrence ◽  
DJ Silverman ◽  
VJ Marder

The clinical manifestations of Rocky Mountain spotted fever (RMSF) result from Rickettsia rickettsii (R rickettsii) infection of endothelial cells and are mediated by pathologic changes localized to the vessel, including in situ thrombosis and tissue ischemia. This study uses in vitro infection of cultured human umbilical vein endothelial cells with R rickettsii to test the hypothesis that such infection induces von Willebrand factor (vWF) release from Weibel- Palade bodies, a process that could contribute to thrombotic changes. At 24 hours postinfection, there was an increase in metabolically prelabeled large multimers of vWF in the culture medium, with a concomitant decrease of these forms in the cell lysate samples. This release reaction was specific for the large multimer pool of vWF, localized to Weibel-Palade bodies, because no change in the distribution of dimeric forms between cells and culture medium was detected. Double-label immunofluorescence staining showed an inverse correlation between the number of R rickettsii and the number of Weibel- Palade bodies in infected cells. Cell lysis was minimal at 24 hours postinfection, as no detectable intracellular precursor forms (molecular weight 260,000) of vWF were released into the culture medium, there was no decrease in cell viability as measured by trypan blue exclusion, and no increase in 51Cr-release into the culture medium was observed when compared with uninfected controls. Release was likely a direct effect of the intracellular presence of the organism, rather than due to a noxious soluble factor such as endotoxin, because culture medium conditioned by infected endothelial cells was ineffective at inducing release in uninfected endothelial cell cultures. In summary, in vitro infection of endothelial cells by R rickettsii induces release of Weibel-Palade body contents, a process that may contribute to the pathogenesis of RMSF.


1987 ◽  
Author(s):  
D D Wagner ◽  
P J Fay ◽  
L A Sporn ◽  
S Sinha ◽  
S O Lawrence ◽  
...  

The intracellular site of cleavage of pro-von Willebrand factor subunit and the subsequent fate of the propolypeptide (von Willebrand antigen II) and of the mature von Willebrand factor (vWf) were investigated. Both the propolypeptide, which was found to be a homodimer of non-covalently linked subunits, and mature vWf were released from Weibel-Palade bodies of endothelial cells following stimulation with secretagogues. The stoichiometry of the two proteins in the releasate was essentially equimolar. This indicates that vWf and the propolypeptide were packaged into the Weibel-Palade bodies as one unit, pro-vWf, and that the proteolytic cleavage of pro-vWf is likely to be a post-Golgi event. The association of prosequences into dimers provides support for their hypothetical role in the multimerization process. After secretion, the two proteins were distributed differently, as based on the following observations. The propolypeptide did not associate with vWf in the culture medium, did not co-distribute with vWf in the extracellular "patches of release" on stimulated endothelial cells, and was not detected in the endothelial cell extracellular matrix, which did contain vWf. Additionally, in contrast to vWf, the propolypeptide did not bind to matrix of human foreskin fibroblasts. Since the propolypeptide does not associate with vWf and does not interact witji extracellular matrices in vitro, it is highly unlikely that it would promote platelet adhesion to subendothelium in vivo.


1993 ◽  
Vol 70 (04) ◽  
pp. 707-711 ◽  
Author(s):  
Andrew D Blann ◽  
Charles N McCollum

SummaryThe effect of smoking on the blood vessel intima was examined by comparing indices of endothelial activity in serum from smokers with that from non-smokers. Serum from smokers contained higher levels of von Willebrand factor (p <0.01), the smoking markers cotinine (p <0.02) and thiocyanate (p <0.01), and was more cytotoxic to endothelial cells in vitro (p <0.02) than serum from non-smokers. The acute effects of smoking two unfiltered medium tar cigarettes was to briefly increase von Willebrand factor (p <0.001) and cytotoxicity of serum to endothelial cells in vitro (p <0.005), but lipid peroxides or thiocyanate were not increased by this short exposure to tobacco smoke. Although there were correlations between von Willebrand factor and smokers consumption of cigarettes (r = 0.28, p <0.02), number of years smoking (r = 0.41, p <0.001) and cotinine (r = 0.45, p <0.01), the tissue culture of endothelial cells with physiological levels of thiocyanate or nicotine suggested that these two smoking markers were not cytotoxic. They are therefore unlikely to be directly responsible for increased von Willebrand factor in the serum of smokers. We suggest that smoking exerts a deleterious influence on the endothelium and that the mechanism is complex.


1997 ◽  
Vol 77 (06) ◽  
pp. 1182-1188 ◽  
Author(s):  
Ulrich M Vischer ◽  
Claes B Wollheinn

Summaryvon Willebrand factor (vWf) is released from endothelial cell storage granules after stimulation with thrombin, histamine and several other agents that induce an increase in cytosolic free calcium ([Ca2+]i). In vivo, epinephrine and the vasopressin analog DDAVP increase vWf plasma levels, although they are thought not to induce vWf release from endothelial cells in vitro. Since these agents act via a cAMP-dependent pathway in responsive cells, we examined the role of cAMP in vWf secretion from cultured human umbilical vein endothelial cells. vWf release increased by 50% in response to forskolin, which activates adenylate cyclase. The response to forskolin was much stronger when cAMP degradation was blocked with IBMX, an inhibitor of phosphodiesterases (+200%), whereas IBMX alone had no effect. vWf release could also be induced by the cAMP analogs dibutyryl-cAMP (+40%) and 8-bromo-cAMP (+25%); although their effect was weak, they clearly potentiated the response to thrombin. Epinephrine (together with IBMX) caused a small, dose-dependent increase in vWf release, maximal at 10-6 M (+50%), and also potentiated the response to thrombin. This effect is mediated by adenylate cyclase-coupled β-adrenergic receptors, since it is inhibited by propranolol and mimicked by isoproterenol. In contrast to thrombin, neither forskolin nor epinephrine caused an increase in [Ca2+]j as measured by fura-2 fluorescence. In addition, the effects of forskolin and thrombin were additive, suggesting that they act through distinct signaling pathways. We found a close correlation between cellular cAMP content and vWf release after stimulation with epinephrine and forskolin. These results demonstrate that cAMP-dependent signaling events are involved in the control of exocytosis from endothelial cells (an effect not mediated by an increase in [Ca2+]i) and provide an explanation for epinephrine-induced vWf release.


2016 ◽  
Vol 116 (07) ◽  
pp. 87-95 ◽  
Author(s):  
D'Andra Parker ◽  
Subia Tasneem ◽  
Richard Farndale ◽  
Dominique Bihan ◽  
J. Sadler ◽  
...  

SummaryMultimerin 1 (MMRN1) is a massive, homopolymeric protein that is stored in platelets and endothelial cells for activation-induced release. In vitro, MMRN1 binds to the outer surfaces of activated platelets and endothelial cells, the extracellular matrix (including collagen) and von Willebrand factor (VWF) to support platelet adhesive functions. VWF associates with MMRN1 at high shear, not static conditions, suggesting that shear exposes cryptic sites within VWF that support MMRN1 binding. Modified ELISA and surface plasmon resonance were used to study the structural features of VWF that support MMRN1 binding, and determine the affinities for VWF-MMRN1 binding. High shear microfluidic platelet adhesion assays determined the functional consequences for VWF-MMRN1 binding. VWF binding to MMRN1 was enhanced by shear exposure and ristocetin, and required VWF A1A2A3 region, specifically the A1 and A3 domains. VWF A1A2A3 bound to MMRN1 with a physiologically relevant binding affinity (KD: 2.0 ± 0.4 nM), whereas the individual VWF A1 (KD: 39.3 ± 7.7 nM) and A3 domains (KD: 229 ± 114 nM) bound to MMRN1 with lower affinities. VWF A1A2A3 was also sufficient to support the adhesion of resting platelets to MMRN1 at high shear, by a mechanism dependent on VWF-GPIbD binding. Our study provides new information on the molecular basis of MMRN1 binding to VWF, and its role in supporting platelet adhesion at high shear. We propose that at sites of vessel injury, MMRN1 that is released following activation of platelets and endothelial cells, binds to VWF A1A2A3 region to support platelet adhesion at arterial shear rates.


1992 ◽  
Vol 286 (2) ◽  
pp. 631-635 ◽  
Author(s):  
M A Carew ◽  
E M Paleolog ◽  
J D Pearson

Secretion of von Willebrand factor (vWf) glycoprotein from storage granules in human umbilical-vein endothelial cells was studied in vitro. Either elevation of intracellular Ca2+ concentration ([Ca2+]i) with a Ca2+ ionophore or activation of protein kinase (PK) C by phorbol 12-myristate 13-acetate caused vWf secretion, and together the agents acted synergistically. However, when vWf release was stimulated by receptor-mediated agonists, selective inhibition of PKC had no effect on histamine-induced secretion and significantly elevated thrombin-induced secretion. Furthermore, ATP, which efficiently elevates [Ca2+]i in these cells, was a very poor effector of vWf release. We conclude that elevation of [Ca2+]i by physiological agonists is necessary for vWf release, but other signalling mechanisms, as yet uncharacterized, but not due to PKC activation, are required for full induction of the secretory pathway.


Blood ◽  
1993 ◽  
Vol 82 (7) ◽  
pp. 2109-2116
Author(s):  
F George ◽  
P Brouqui ◽  
MC Boffa ◽  
M Mutin ◽  
M Drancourt ◽  
...  

The endothelial cell (EC) is the primary target for Rickettsia conorii (RC) in Mediterranean spotted fever (MSF). Clinical manifestations such as thrombosis and vasculitis are mediated by pathologic changes localized in blood vessels. To study the in vivo endothelial injury induced by RC, markers of endothelial damage, including circulating EC (CEC), plasmatic thrombomodulin (TM), and von Willebrand factor (vWF), were investigated in 12 patients with MSF. CEC were counted in whole blood by a new immunomagnetic separation assay using a specific anti-EC antibody, S-Endo 1. Plasmatic TM and vWF antigens were measured by enzyme-linked immunosorbent assay. High levels of CEC and cell fragments were found in patients with a severe or malignant form of MSF. Sequential studies of CEC showed a decrease from 162 +/- 454 cells/mL before treatment to 6 +/- 7 cells/mL during treatment and recovery. Mean plasma TM and vWF levels that were also elevated before therapy (TM, 106 +/- 27 ng/mL; vWF, 420% +/- 164%) decreased progressively (TM, 55 +/- 43 ng/mL; vWF, 148% +/- 26%) during treatment. The measurement of cellular and molecular markers of vascular damage such as CEC, plasmatic TM, and vWF contributes to the definition of the Rickettsia-induced endothelial injury in vivo.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 290-290 ◽  
Author(s):  
Anil K. Chauhan ◽  
Janka Kiucka ◽  
Alexander Brill ◽  
Meghan T. Walsh ◽  
Denisa D. Wagner

Abstract von Willebrand factor (VWF) is synthesized in megakaryocytes and endothelial cells and stored in a-granules and Weibel-Palade bodies, respectively. VWF levels are elevated in both chronic and acute inflammation. ADAMTS13 (A D isintegrin-like A nd M etalloprotease with T hrombo s pondin type I repeats-13) is a metalloprotease that cleaves ultra large von Willebrand factor (ULVWF) multimers quickly after its release from endothelium. Recent studies have found that VWF promotes leukocyte adhesion in vitro and that ADAMTS13 activity is reduced in inflammation and sepsis. We hypothesized that by cleaving ULVWF multimers, ADAMTS13 not only inhibits thrombosis, but also attenuates leukocyte rolling and adhesion. Using intravital microscopy, we found more leukocyte rolling/min on the unstimulated veins in Adamts13-/- mice (Mean ± SE: 98 ± 16) compared to WT (Mean ± SE: 35 ± 6, P<0.001), n=18–20 from 10–11 mice per group. This process was dependent on VWF because the number of leukocytes rolling in Adamts13-/-/Vwf-/- veins was similar to that in Vwf-/-. Significantly increased soluble P-selectin and VWF concentrations were found in the plasma of Adamts13-/- compared to WT mice as quantitated by ELISA. In addition, endothelial P-selectin surface expression was increased in Adamts13-/- mice compared to WT. These results suggest elevated release of Weibel-Palade bodies in Adamts13-/- mice. Notably, circulating platelets were not activated in the absence of ADAMTS13. Upon stimulation of the mesentery with histamine, leukocyte rolling was slower in Adamts13-/- veins compared to WT. Furthermore, upon stimulation with the inflammatory cytokine TNF-alpha (i.v) 3.5 h prior to surgery, the number of leukocytes adhering/250 um was significantly increased in microvenules (diameter of 25–30 um) of Adamts13-/- mice (Mean ± SD: 21 ± 6) compared to WT (Mean ± SD: 12 ± 5, P<0.001), n=10–11 mice per group. This firm adhesion was also dependent on VWF because the number of adherent leukocytes in veins of Adamts13-/-/Vwf-/- was similar to Vwf-/-. Our studies indicate a crucial role for ADAMTS13 in preventing excessive spontaneous Weibel-Palade secretion and in attenuating leukocyte rolling and adhesion to ultra large VWF presented by endothelial cells during inflammation.


Blood ◽  
1993 ◽  
Vol 82 (7) ◽  
pp. 2109-2116 ◽  
Author(s):  
F George ◽  
P Brouqui ◽  
MC Boffa ◽  
M Mutin ◽  
M Drancourt ◽  
...  

Abstract The endothelial cell (EC) is the primary target for Rickettsia conorii (RC) in Mediterranean spotted fever (MSF). Clinical manifestations such as thrombosis and vasculitis are mediated by pathologic changes localized in blood vessels. To study the in vivo endothelial injury induced by RC, markers of endothelial damage, including circulating EC (CEC), plasmatic thrombomodulin (TM), and von Willebrand factor (vWF), were investigated in 12 patients with MSF. CEC were counted in whole blood by a new immunomagnetic separation assay using a specific anti-EC antibody, S-Endo 1. Plasmatic TM and vWF antigens were measured by enzyme-linked immunosorbent assay. High levels of CEC and cell fragments were found in patients with a severe or malignant form of MSF. Sequential studies of CEC showed a decrease from 162 +/- 454 cells/mL before treatment to 6 +/- 7 cells/mL during treatment and recovery. Mean plasma TM and vWF levels that were also elevated before therapy (TM, 106 +/- 27 ng/mL; vWF, 420% +/- 164%) decreased progressively (TM, 55 +/- 43 ng/mL; vWF, 148% +/- 26%) during treatment. The measurement of cellular and molecular markers of vascular damage such as CEC, plasmatic TM, and vWF contributes to the definition of the Rickettsia-induced endothelial injury in vivo.


Sign in / Sign up

Export Citation Format

Share Document