Zsuzsanna Németh1, Márta L. Debreczeni1, József Dobó2, Péter Gál2, László Cervenak1
1 3rd Department of Internal Medicine, Semmelweis University, Budapest
2 Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest
Activation of the endothelium towards an increased vascular permeability can lead to the development of severe, life-threatening edematous attacks, for example in the case of hereditary angioedema (HAE) or sepsis. Both exogenous (e.g. bacterial LPS) and endogenous (e.g. complement factors) inflammatory components play a role in the pathomechanism of these diseases. Therefore, we wanted to investigate how these various components (mannan-binding lectin-associated serine protease 1 – MASP-1, histamine, bradykinin and LPS) can interact with one another to influence endothelial cell permeability.
In our earlier studies, we showed that MASP-1 can directly increase endothelial permeability and activate the expression of permeability related genes, including the B2 bradykinin receptor (BDKRB2). We measured the mRNA level of BDKRB1 and 2 with qPCR and found that MASP-1 up-regulated the level of BDKRB2, while LPS increased the expression of both bradykinin receptors. In concert with this, the MASP-1 or LPS pretreated cells showed significantly greater Ca2+-mobilization to bradykinin than those that were not pretreated (measured with fluorescence microscopy).
LPS also induced the mRNA level of HRH1 and PAR2, which are receptors of histamine and MASP-1, respectively, on endothelial cells. Furthermore, we demonstrated that these factors elicited greater Ca2+-mobilization after LPS pretreatment.
To measure the endothelial permeability, we used the modified X-per-T method. The LPS pretreatment could significantly increase endothelial permeability in response to MASP-1.
Our findings highlight that significant interaction can occur amongst endothelial cell activators (between LPS and MASP-1, LPS and bradykinin, LPS and histamine, and MASP-1 and bradykinin) in the regulation of endothelial cell permeability. These synergistic interactions may give us a more detailed picture on the pathogenesis of HAE and sepsis, as well as on their potential therapeutic approaches.
Doctoral School: Basic and Translational Medicine
Program: Vascular Pathophysiology / Atherosclerosis
Supervisor: László Cervenak
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