P2Y14 receptor activation of platelets induces Ca2+ mobilization and
Rho-GTPase dependent motility that requires an interaction with P2Y1
receptors.
Abstract
Background and Purpose: Platelet function during inflammation is
dependent on activation by endogenous nucleotides acting on purinergic
receptors. The P2Y14 receptor (P2Y14R) has been reported to be expressed
on platelets and is involved in leukocyte recruitment during
inflammation. However, a role for P2Y14R receptors on platelet function
has not yet been determined. Experimental Approach: Platelets obtained
from healthy human volunteers were incubated with the P2Y14R agonist,
UDP-Glucose (UDP-G), and PPTN, a selective P2Y14R antagonist. Platelet
activation was quantified using Ca2+ mobilization, aggregation, and
chemotaxis assays. Cooperativity with P2Y1 receptor (P2Y1R) activation
was also assessed after stimulation with UDP-G in the presence of
MRS2500, a selective P2Y1R antagonist. Key Results: Ca2+ mobilization
occurred in platelets after incubation with UDP-G in a
concentration-dependent manner, and this was suppressed in platelets
treated with PPTN. Platelets did not aggregate, or bind to fibrinogen
after incubation with UDP-G. However, platelet chemotaxis towards f-MLP
was dependent on P2Y14R stimulation with UDP-G and this was reduced by
Rho-GTPase inhibitors. Furthermore, UDP-G induced Ca2+ mobilization and
chemotaxis were also inhibited when platelets were pretreated with
MRS2500. Conversely, ADP induced Ca2+ mobilization, chemotaxis and
aggregation were not affected by the incubation with PPTN. Conclusion
and Implications: Platelets can be activated via P2Y14R stimulation to
induce chemotaxis but not aggregation. Furthermore, this was dependent
on concomitant activation of P2Y1R. Activation of P2Y14Rs on platelets
may therefore be relevant during inflammation, but cooperation with
P2Y1R activation is required.