Protease activated receptor signaling is required for African trypanosome traversal of human brain microvascular endothelial cells.

<h4>Background</h4>Using human brain microvascular endothelial cells (HBMECs) as an in vitro model for how African trypanosomes cross the human blood-brain barrier (BBB) we recently reported that the parasites cross the BBB by generating calcium activation signals in HBMECs through the a...

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Autores principales: Dennis J Grab, Jose C Garcia-Garcia, Olga V Nikolskaia, Yuri V Kim, Amanda Brown, Carlos A Pardo, Yongqing Zhang, Kevin G Becker, Brenda A Wilson, Ana Paula C de A Lima, Julio Scharfstein, J Stephen Dumler
Formato: article
Lenguaje:EN
Publicado: Public Library of Science (PLoS) 2009
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Acceso en línea:https://doaj.org/article/57eeeeb3c8e24f6f84c9d7feca2de86e
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Sumario:<h4>Background</h4>Using human brain microvascular endothelial cells (HBMECs) as an in vitro model for how African trypanosomes cross the human blood-brain barrier (BBB) we recently reported that the parasites cross the BBB by generating calcium activation signals in HBMECs through the activity of parasite cysteine proteases, particularly cathepsin L (brucipain). In the current study, we examined the possible role of a class of protease stimulated HBMEC G protein coupled receptors (GPCRs) known as protease activated receptors (PARs) that might be implicated in calcium signaling by African trypanosomes.<h4>Methodology/principal findings</h4>Using RNA interference (RNAi) we found that in vitro PAR-2 gene (F2RL1) expression in HBMEC monolayers could be reduced by over 95%. We also found that the ability of Trypanosoma brucei rhodesiense to cross F2RL1-silenced HBMEC monolayers was reduced (39%-49%) and that HBMECs silenced for F2RL1 maintained control levels of barrier function in the presence of the parasite. Consistent with the role of PAR-2, we found that HBMEC barrier function was also maintained after blockade of Galpha(q) with Pasteurella multocida toxin (PMT). PAR-2 signaling has been shown in other systems to have neuroinflammatory and neuroprotective roles and our data implicate a role for proteases (i.e. brucipain) and PAR-2 in African trypanosome/HBMEC interactions. Using gene-profiling methods to interrogate candidate HBMEC pathways specifically triggered by brucipain, several pathways that potentially link some pathophysiologic processes associated with CNS HAT were identified.<h4>Conclusions/significance</h4>Together, the data support a role, in part, for GPCRs as molecular targets for parasite proteases that lead to the activation of Galpha(q)-mediated calcium signaling. The consequence of these events is predicted to be increased permeability of the BBB to parasite transmigration and the initiation of neuroinflammation, events precursory to CNS disease.