Abstract
With a newer, more selective and efficacious cytosolic phospholipase A<inf>2</inf>α (cPLA<inf>2</inf>α) inhibitor available, we revisited the role of cPLA<inf>2</inf>α activity in platelet activation and discovered that a component of platelet signaling, even larger than previously appreciated, relies on this enzyme. In a whole blood shear-based flow chamber assay, giripladib, a cPLA<inf>2</inf>α inhibitor, reduced platelet adhesion and accumulation on collagen. Moreover, giripladib differentially affected P-selectin expression and GPIIbIIIa activation depending on the agonist employed. While protease-activated receptor 1 (PAR1)-mediated platelet activation was unaffected by giripladib, the levels of PAR4- and GPVI-mediated platelet activation were significantly reduced. Meanwhile, the thromboxane A<inf>2</inf> receptor antagonist SQ29548 had no effect on PAR-, GPVI-, or puriniergic receptor-mediated platelet activation, suggesting that another eicosanoid produced downstream of arachidonic acid liberation by cPLA<inf>2</inf>α was responsible for this large component of PAR4- and GPVI-mediated platelet activation. In parallel, we profiled PAR-mediated changes in glycerophospholipid (GPL) mass with and without giripladib to better understand cPLA<inf>2</inf>α-mediated lipid metabolism. Phosphatidylcholine and phosphatidylethanolamine (PE) demonstrated the largest consumption of mass during thrombin stimulation. Additionally, we confirm phosphatidylinositol as a major substrate of cPLA<inf>2</inf>α. A comparison of PAR1- and PAR4-induced metabolism revealed the consumption of more putative arachidonyl-PE species downstream of PAR1 activation. Instead of enhanced cPLA<inf>2</inf>α activity and therefore more arachidonic acid liberation downstream of PAR4, these results indicate the major role that cPLA<inf>2</inf>α activity plays in platelet function and suggest that a novel eicosanoid is produced in response to platelet activation that represents a large component of PAR4- and GPVI-mediated responses.
| Original language | English |
|---|---|
| Pages (from-to) | 5578-5588 |
| Number of pages | 11 |
| Journal | Biochemistry |
| Volume | 54 |
| Issue number | 36 |
| DOIs | |
| Publication status | Published - 15 Sep 2015 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Platelet Lipidomic Profiling : Novel Insight into Cytosolic Phospholipase A<inf>2</inf>α Activity and Its Role in Human Platelet Activation. / Duvernay, Matthew T.; Matafonov, Anton; Lindsley, Craig W.; Hamm, Heidi E.
In: Biochemistry, Vol. 54, No. 36, 15.09.2015, p. 5578-5588.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Platelet Lipidomic Profiling
T2 - Novel Insight into Cytosolic Phospholipase A2α Activity and Its Role in Human Platelet Activation
AU - Duvernay, Matthew T.
AU - Matafonov, Anton
AU - Lindsley, Craig W.
AU - Hamm, Heidi E.
PY - 2015/9/15
Y1 - 2015/9/15
N2 - With a newer, more selective and efficacious cytosolic phospholipase A2α (cPLA2α) inhibitor available, we revisited the role of cPLA2α activity in platelet activation and discovered that a component of platelet signaling, even larger than previously appreciated, relies on this enzyme. In a whole blood shear-based flow chamber assay, giripladib, a cPLA2α inhibitor, reduced platelet adhesion and accumulation on collagen. Moreover, giripladib differentially affected P-selectin expression and GPIIbIIIa activation depending on the agonist employed. While protease-activated receptor 1 (PAR1)-mediated platelet activation was unaffected by giripladib, the levels of PAR4- and GPVI-mediated platelet activation were significantly reduced. Meanwhile, the thromboxane A2 receptor antagonist SQ29548 had no effect on PAR-, GPVI-, or puriniergic receptor-mediated platelet activation, suggesting that another eicosanoid produced downstream of arachidonic acid liberation by cPLA2α was responsible for this large component of PAR4- and GPVI-mediated platelet activation. In parallel, we profiled PAR-mediated changes in glycerophospholipid (GPL) mass with and without giripladib to better understand cPLA2α-mediated lipid metabolism. Phosphatidylcholine and phosphatidylethanolamine (PE) demonstrated the largest consumption of mass during thrombin stimulation. Additionally, we confirm phosphatidylinositol as a major substrate of cPLA2α. A comparison of PAR1- and PAR4-induced metabolism revealed the consumption of more putative arachidonyl-PE species downstream of PAR1 activation. Instead of enhanced cPLA2α activity and therefore more arachidonic acid liberation downstream of PAR4, these results indicate the major role that cPLA2α activity plays in platelet function and suggest that a novel eicosanoid is produced in response to platelet activation that represents a large component of PAR4- and GPVI-mediated responses.
AB - With a newer, more selective and efficacious cytosolic phospholipase A2α (cPLA2α) inhibitor available, we revisited the role of cPLA2α activity in platelet activation and discovered that a component of platelet signaling, even larger than previously appreciated, relies on this enzyme. In a whole blood shear-based flow chamber assay, giripladib, a cPLA2α inhibitor, reduced platelet adhesion and accumulation on collagen. Moreover, giripladib differentially affected P-selectin expression and GPIIbIIIa activation depending on the agonist employed. While protease-activated receptor 1 (PAR1)-mediated platelet activation was unaffected by giripladib, the levels of PAR4- and GPVI-mediated platelet activation were significantly reduced. Meanwhile, the thromboxane A2 receptor antagonist SQ29548 had no effect on PAR-, GPVI-, or puriniergic receptor-mediated platelet activation, suggesting that another eicosanoid produced downstream of arachidonic acid liberation by cPLA2α was responsible for this large component of PAR4- and GPVI-mediated platelet activation. In parallel, we profiled PAR-mediated changes in glycerophospholipid (GPL) mass with and without giripladib to better understand cPLA2α-mediated lipid metabolism. Phosphatidylcholine and phosphatidylethanolamine (PE) demonstrated the largest consumption of mass during thrombin stimulation. Additionally, we confirm phosphatidylinositol as a major substrate of cPLA2α. A comparison of PAR1- and PAR4-induced metabolism revealed the consumption of more putative arachidonyl-PE species downstream of PAR1 activation. Instead of enhanced cPLA2α activity and therefore more arachidonic acid liberation downstream of PAR4, these results indicate the major role that cPLA2α activity plays in platelet function and suggest that a novel eicosanoid is produced in response to platelet activation that represents a large component of PAR4- and GPVI-mediated responses.
UR - http://www.scopus.com/inward/record.url?scp=84941686997&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84941686997&partnerID=8YFLogxK
U2 - 10.1021/acs.biochem.5b00549
DO - 10.1021/acs.biochem.5b00549
M3 - Article
C2 - 26295742
AN - SCOPUS:84941686997
VL - 54
SP - 5578
EP - 5588
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 36
ER -