title: PI3-kinase is essential for ADP-stimulated integrin alpha(IIb)beta3-mediated platelet calcium oscillation, implications for P2Y receptor pathways in integrin alpha(IIb)beta3-initiated signaling cross-talks.
abstract: Phosphatidylinositol 3-kinase (PI3K) pathway is important for platelet activation. Recent studies showed that PI3K and oscillative calcium could cross talk to each other and positively regulate integrin alpha (IIb)beta3-mediated outside-in signaling. However, the mechanism of this feedback regulation remains to be further characterized. Here we found that treatments of both PI3K inhibitor wortmannin and P2Y1 inhibitor A3P5P could inhibit granular secretion in platelets. Additionally, when RGD-substrate adherent platelets were treated with the ADP scavenger apyrase to deplete the granular-released ADP, their attachments in engaging with substrates became looser and the frequency of calcium oscillation decreased. Since it is known that ADP stimulates the PI3K and calcium signal primarily through P2Y12 and P2Y1 receptors respectively, our data indicated that integrin alpha(IIb)beta3 downstream PI3K and calcium activation might be not completely coupled to integrin associated signaling complex, but in part through feedback stimulation by granular released ADP. Our data indicates the important roles of PI3K and granular released ADP in coordinating the feedback regulations in integrin alpha(IIb)beta3-mediated platelet activation.
authors.affiliation: Institute of Human Genetics, Tzu-Chi University, Hualien 970, Taiwan, Republic of China.
authors.forename: Der-Shan
authors.initials: DS
authors.lastname: Sun
authors.forename: Szecheng J
authors.initials: SJ
authors.lastname: Lo
authors.forename: Wei-Jern
authors.initials: WJ
authors.lastname: Tsai
authors.forename: Chi-Hung
authors.initials: CH
authors.lastname: Lin
authors.forename: Mei-Shiuan
authors.initials: MS
authors.lastname: Yu
authors.forename: Yao-Fong
authors.initials: YF
authors.lastname: Chen
authors.forename: Hsin-Hou
authors.initials: HH
authors.lastname: Chang
mesh_terms: D000199:Actins / Q000737:chemistry; D000244:Adenosine Diphosphate / Q000737:chemistry / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology; D001792:Blood Platelets / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002448:Cell Adhesion; D058534:Class I Phosphatidylinositol 3-Kinases; D003599:Cytoskeleton / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000378:metabolism; D005340:Fibrinogen / Q000737:chemistry; D006801:Humans; D016023:Integrins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D018613:Microscopy, Confocal; D018715:Microscopy, Video; D015233:Models, Statistical; D009991:Oscillometry; D019007:P-Selectin / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism / Q000502:physiology*; D010957:Plasmids / Q000378:metabolism; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000378:metabolism; D058472:Receptors, Purinergic P2Y1; D058925:Receptors, Purinergic P2Y12; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D015398:Signal Transduction; D013997:Time Factors; D000077191:Wortmannin
chemical_list: D000199:Actins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000730:Androstadienes; D002118:Calcium; D058534:Class I Phosphatidylinositol 3-Kinases; D005340:Fibrinogen; D016023:Integrins; D008565:Membrane Proteins; D019007:P-Selectin; D010455:Peptides; D019869:Phosphatidylinositol 3-Kinases; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D058925:Receptors, Purinergic P2Y12; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D000077191:Wortmannin; C546382:P2RY1 protein, human; C548576:P2RY12 protein, human; C072026:rhodostomin; C484760:PIK3CA protein, human