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Principal Investigator: MICHAEL Allan HOLINSTAT
Organization: UNIVERSITY OF MICHIGAN AT ANN ARBOR
Fiscal Year: 2021
Award: $146,455
Funding agency: National Institute of General Medical Sciences
ABSTRACT
Platelets play an essential role in the vessel, maintaining hemostasis and normal blood flow following vascular
insult or injury under physiological conditions. While activation of the platelet is essential for adhesion and
aggregation to occur at the site of vascular injury, excessive platelet reactivity can lead to the formation of
occlusive thrombi, the predominant underlying cause of myocardial infarction and stroke. Current anti-platelet
treatments have significantly limited morbidity and mortality due to thrombosis, however they often result in an
increased risk of bleeding resulting in a need for novel targets to further decrease platelet reactivity while
exhibiting a limited increased risk for bleeding. Our lab and others have provided compelling evidence
supporting 12-lipoxygenase (12-LOX), an enzyme highly expressed in the platelet whose primary function is
thought to be to produce bioactive oxidized lipids (oxylipins) from the fatty acids embedded in the platelet
membrane, as playing an important role in the regulation of platelet activation. The role of newly studied fatty
acids in the platelet such as DGLA, DHA, and EPA has yielded strong preliminary data supporting fatty acids
and their 12-LOX oxylipins as being important for regulation of platelet function through GPCR and non-GPCR
mechanisms. Our lab has identified the first 12-LOX negative regulation pathway in the platelet whereby
formation of 12(S)-HETrE induces activation of a Gs-coupled GPCR pathway and activation of PKA resulting in
inhibition of platelet activation and clot formation in vivo while not causing an observed increase in bleeding.
We propose to investigate the underlying mechanisms by which these 12-LOX oxylipins regulate
platelet activity, clotting, and thrombosis while only minimally affecting bleeding. Therefore, we will
assess how DGLA and its oxylipin 12(S)-HETrE alters the phospho-proteome through activation of PKA,
elucidate the mechanism by which DHA and EPA regulate platelet function and clotting both ex vivo and in vivo
through their 12-LOX oxylipins while sparing hemostasis, and assess the mechanism by which the DHA 12-
LOX oxylipin 14-HpDHA can be oxidized to form a new class of maresins, Mar1-D3, in order to regulate
thrombolysis and clot resolution. Preliminary data suggests the platelet may produce a novel pool for this pro-
resolving oxylipins that could play an important role in the underlying mechanism of clot resolution in vivo.
Successful completion of this study will for the first time define the mechanism by which 12-LOX oxylipins
regulate platelet reactivity in order to both prevent clot formation and resolve pre-existing clots. Understanding
these complex signaling pathways represents a seminal advancement in our understanding of how oxylipins
like 12(S)-HETrE regulate the blood and will enable for identification of new targets on the platelet for
development of the next generation of anti-platelet therapeutics with the added benefit of limited bleeding.
Terms: <12-Lipoxygenase><Adenosine Cyclic Monophosphate-Dependent Protein Kinases><Adhesions><Affect><Age><Apoplexy><Arachidonate 12-Lipoxygenase><Arachidonic Acid 12-Lipoxygenase><Bleeding><Blood><Blood Clotting><Blood Platelets><Blood Reticuloendothelial System><Blood Vessels><Blood coagulation><Blood flow><Brain Vascular Accident><Cardiac infarction><Cell Communication and Signaling><Cell Signaling><Cerebral Stroke><Cerebrovascular Apoplexy><Cerebrovascular Stroke><Clotting><Coagulation><Coagulation Process><Complex><Coupled><Cyclic AMP-Dependent Protein Kinases><Data><Development><Enzyme Gene><Enzymes><Equipment><Event><Exhibits><Fatty Acids><Flow Cytofluorometries><Flow Cytofluorometry><Flow Cytometry><Flow Microfluorimetry><Flow Microfluorometry><G Protein-Complex Receptor><G Protein-Coupled Receptor Genes><G(s), alpha Subunit><G(s), α Subunit><G(s)alpha><G(s)α><G-Protein-Coupled Receptors><GPCR><GTP-Binding Protein alpha Subunits, Gs><GTP-Binding Protein α Subunits, Gs><Gs alpha Family G-Protein><Gsα><Gαs><Hemorrhage><Hemostasis><Hemostatic function><Injury><Intracellular Communication and Signaling><LOX><LOX gene><Laser Electromagnetic><Laser Radiation><Lasers><Lead><Marrow platelet><Membrane><Morbidity><Morbidity - disease rate><Myocardial Infarct><Myocardial Infarction><Oxides><PKA><Pansy><Pathway interactions><Pb element><Physiologic><Physiological><Platelet Activation><Platelets><Play><Process><Protein Kinase A><Proteome><Regulation><Regulatory Ns Protein><Resolution><Risk><Robotics><Role><Seminal><Signal Pathway><Signal Transduction><Signal Transduction Systems><Signaling><Site><Stimulatory Gs G-Protein><Stroke><System><Therapeutic><Thrombocytes><Thrombosis><Thrombus><Time><Viola><Violet><ages><alpha Subunit Stimulatory GTP-Binding Protein><alpha-Gs><arm><biological signal transduction><blood loss><brain attack><cAMP-Dependent Protein Kinases><cardiac infarct><cerebral vascular accident><cerebrovascular accident><coronary attack><coronary infarct><coronary infarction><developmental><flow cytophotometry><heart attack><heart infarct><heart infarction><heavy metal Pb><heavy metal lead><in vivo><injuries><injury to the vasculature><membrane structure><mortality><nano particle><nano-sized particle><nanoparticle><nanosized particle><next generation><novel><oxidized lipid><pathway><platelet function><prevent><preventing><social role><thrombolysis><thrombotic disease><thrombotic disorder><vascular><vascular injury><α-Gs>