Fibrinogen induces endothelial cell permeability - PubMed (original) (raw)

Fibrinogen induces endothelial cell permeability

Neetu Tyagi et al. Mol Cell Biochem. 2008 Jan.

Abstract

Many cardiovascular and cerebrovascular disorders are accompanied by an increased blood content of fibrinogen (Fg), a high molecular weight plasma adhesion protein. Fg is a biomarker of inflammation and its degradation products have been associated with microvascular leakage. We tested the hypothesis that at pathologically high levels, Fg increases endothelial cell (EC) permeability through extracellular signal regulated kinase (ERK) signaling and by inducing F-actin formation. In cultured ECs, Fg binding to intercellular adhesion molecule-1 and to alpha(5)beta(1) integrin, caused phosphorylation of ERK. Subsequently, F-actin formation increased and coincided with formation of gaps between ECs, which corresponded with increased permeability of ECs to albumin. Our data suggest that formation of F-actin and gaps may be the mechanism for increased albumin leakage through the EC monolayer. The present study indicates that elevated un-degraded Fg may be a factor causing microvascular permeability that typically accompanies cardiovascular and cerebrovascular disorders.

PubMed Disclaimer

Figures

Fig. 1

Fig. 1

Fg-induced albumin leakage through the endothelial cell monolayer. (A) Fluorescence intensity of bovine serum albumin conjugated with Alexa Flour-555 (BSA-555) in lower chamber of Transwells; (B) Total protein content in lower chamber of Transwells relative to the total protein content in the respective upper chamber. Antibodies to ICAM-1, _α_5 and β_1 integrins, and MEK inhibitors, PD98059 or U0126, were used at concentration of 50 μM each. *P<0.05 versus control, †_P<0.05 versus lower dose of Fg. Number of experiments n = 5 for all groups. Clearly defined _α_-, _β_-, and _γ_-chains of Fg before (left) and after the cell treatment (right) shown by the Coomassie-stained SDS-PAGE analysis (reducing conditions) confirms the purity of the Fg (insert)

Fig. 2

Fig. 2

Fg leakage through the endothelial cell monolayer. Content of FITC-conjugated Fg in lower chamber of Transwells detected by fluorescence intensity measurement. *P<0.05 versus 2 mg/ml Fg, †P<0.05 versus previous time. Number of experiments n = 4

Fig. 3

Fig. 3

Fg-induced F-actin formation in cultured endothelial cells. (A) Examples of images of Fg-induced F-actin formation, (B) Total fluorescence intensity changes of F-actin staining in various groups of treatment. Antibodies to ICAM-1, _α_5 and β_1 integrins, and MEK inhibitors, PD98059 or U0126, were used at concentration of 50 μM each. *P<0.05 versus control. †_P<0.05 versus 2 mg/ml of Fg. #P<0.05 versus 4 mg/ml Fg alone. The arrows indicate the spaces in the endothelial cell monolayer. Each data point represents the results of duplicate determinations from four separate experiments (n = 4)

Fig. 4

Fig. 4

Comparison of Fg- and thrombin-induced F-actin formation in cultured endothelial cells. (A) Examples of images; (B) Fluorescence intensity of labeled F-actin associated with Fg- and thrombin-induced F-actin formation in ECs. *P<0.05 versus control. †P<0.05 versus 0.5 U/ml thrombin. Each data point represents the results of duplicate determinations from three separate experiments (n = 3)

Fig. 5

Fig. 5

Fg-induced ERK phosphorylation in rat cardiac microvascular ECs. (A) Examples of images of Fg-induced ERK phosphorylation (images 2 and 3), and its inhibition in the presence of MEK inhibitors PD98059, and U0126 (images 4 and 5 respectively). Image 1 represents an ERK phosphorylation in cells treated with medium alone (control). (B) Fluorescence intensity per cell associated with Fg-induced ERK phosphorylation. *P<0.05 versus control, †P<0.05 versus 2 mg/ml Fg, #P<0.05 versus 4 mg/ml Fg alone. n = 4

Similar articles

Cited by

References

    1. Huxley V, Curry F. Albumin modulation of capillary permeability: test of an adsorption mechanism. Am J Physiol. 1995;248(2 Pt 2):H264–H273. - PubMed
    1. Huxley V, Curry F. Effect of superfusate albumin on single capillary hydraulic conductivity. Am J Physiol Heart Circ Physiol. 1987;252(2 Pt 2):H395–H401. - PubMed
    1. Mehta D, Malik A. Signaling mechanisms regulating endothelial permeability. Physiol Rev. 2006;86(1):279–367. - PubMed
    1. Danesh J, Lewington S, Thompson SG, Lowe GD, Collins R, Kostis JB, et al. Plasma fibrinogen level and the risk of major cardiovascular diseases and nonvascular mortality: an individual participant meta-analysis. JAMA. 2005;294(14):1799–1809. - PubMed
    1. Ross R. Mechanisms of disease – Atherosclerosis – An inflammatory disease. N Engl J Med. 1999;340(2):115–126. - PubMed

Publication types

MeSH terms

Substances

Grants and funding

LinkOut - more resources