TY  - JOUR
A1  - Gambaryan, Stepan
A1  - Subramanian, Hariharan
A1  - Kehrer, Linda
A1  - Mindukshev, Igor
A1  - Sudnitsyna, Julia
A1  - Reiss, Cora
A1  - Rukoyatkina, Natalia
A1  - Friebe, Andreas
A1  - Sharina, Iraida
A1  - Martin, Emil
A1  - Walter, Ulrich
T1  - Erythrocytes do not activate purified and platelet soluble guanylate cyclases even in conditions favourable for NO synthesis
JF  - Cell Communication and Signaling
N2  - Background
Direct interaction between Red blood cells (RBCs) and platelets is known for a long time. The bleeding time is prolonged in anemic patients independent of their platelet count and could be corrected by transfusion of RBCs, which indicates that RBCs play an important role in hemostasis and platelet activation. However, in the last few years, opposing mechanisms of platelet inhibition by RBCs derived nitric oxide (NO) were proposed. The aim of our study was to identify whether RBCs could produce NO and activate soluble guanylate cyclase (sGC) in platelets.

Methods
To test whether RBCs could activate sGC under different conditions (whole blood, under hypoxia, or even loaded with NO), we used our well-established and highly sensitive models of NO-dependent sGC activation in platelets and activation of purified sGC. The activation of sGC was monitored by detecting the phosphorylation of Vasodilator Stimulated Phosphoprotein (VASPS239) by flow cytometry and Western blot. ANOVA followed by Bonferroni’s test and Student’s t-test were used as appropriate.

Results
We show that in the whole blood, RBCs prevent NO-mediated inhibition of ADP and TRAP6-induced platelet activation. Likewise, coincubation of RBCs with platelets results in strong inhibition of NO-induced sGC activation. Under hypoxic conditions, incubation of RBCs with NO donor leads to Hb-NO formation which inhibits sGC activation in platelets. Similarly, RBCs inhibit activation of purified sGC, even under conditions optimal for RBC-mediated generation of NO from nitrite.

Conclusions
All our experiments demonstrate that RBCs act as strong NO scavengers and prevent NO-mediated inhibition of activated platelets. In all tested conditions, RBCs were not able to activate platelet or purified sGC.
KW  - hemoglobin
KW  - erythrocytes
KW  - nitric oxide
KW  - soluble guanylate cyclase
KW  - platelets
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-161223
VL  - 14
IS  - 16
ER  -