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

Storm, J., Wu, Y., Davies, J., Moxon, C. A. and Craig, A. G. (2020) Testing the effect of PAR1 inhibitors on Plasmodium falciparum-induced loss of endothelial cell barrier function. Wellcome Open Research, 5, 34. (doi: 10.12688/wellcomeopenres.15602.3) (PMID:32724861) (PMCID:PMC7364184)

Abstract

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, PAR1 inhibitors did not rescue the barrier dysfunction after co-culture with IE lysate. 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.

• Item Type: Articles
• Additional Information: Version 3; peer review: 2 approved. This work was funded by a Wellcome Trust Senior Investigator Award (ref: 095507) and a Medical Research Council, Confidence in Concept Award (ref: MCPC16052) to AGC and a Wellcome Trust Seed Award (ref: 109698/Z/15/Z) and an award from the Academy of Medical Sciences (SGL014\12) to CAM.
• Keywords: PAR1, Plasmodium falciparum, barrier function, cerebral malaria, endothelium, thrombin.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Storm, Dr Janet and Moxon, Dr Christopher

Creator Roles

Storm, J.: Formal analysis, Investigation, Methodology, Project administration, Validation, Visualization, Writing – original draft
Moxon, C. A.: Conceptualization, Methodology, Project administration, Supervision, Validation, Writing – review and editing

• Authors: Storm, J., Wu, Y., Davies, J., Moxon, C. A., and Craig, A. G.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Wellcome Open Research
• Publisher: F1000Research
• ISSN: 2398-502X
• ISSN (Online): 2398-502X
• Copyright Holders: Copyright © 2020 Storm J et al.
• First Published: First published in Wellcome Open Research 5: 34
• Publisher Policy: Reproduced under a Creative Commons License
• Data DOI: 10.6084/m9.figshare.11558889

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
166225		Cytoadherence-mediated pathology in cerebral malaria	James Brewer	Wellcome Trust (WELLCOTR)	095507/Z/11/Z	III - Immunology