AlphaB-crystallin, a low-molecular-weight heat shock protein, acts as a regulator of platelet function.
It has recently been reported that alphaB-crystallin, a low-molecular-weight heat shock protein, may be released from cells by mechanical stretch. We investigated a physiological role of alphaB-crystallin in platelet function. AlphaB-crystallin inhibited platelet aggregation induced by thrombin or botrocetin in hamsters and humans. These platelets had specific binding sites for alphaB-crystallin. Moreover, alphaB-crystallin significantly reduced thrombin-induced Ca2+ influx and phosphoinositide hydrolysis by phospholipase C in human platelets. Additionally, plasma levels of alphaB-crystallin were markedly elevated in cardiomyopathic hamsters. Levels of alphaB-crystallin in vessel walls after endothelial injury were markedly reduced. Therefore, our results suggest that alphaB-crystallin, which is discharged from vessel walls in response to endothelial injury, acts intercellularly as a regulator of platelet function.
Kozawa
O
O
Department of Pharmacology, Gifu University School of Medicine, Japan. okozawa@cc.gifu-u.ac.jp
Matsuno
H
H
Niwa
M
M
Hatakeyama
D
D
Kato
K
K
Uematsu
T
T
D000818:Animals; D001792:Blood Platelets / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D009202:Cardiomyopathies / Q000188:drug therapy / Q000378:metabolism; D002339:Carotid Arteries / Q000737:chemistry / Q000378:metabolism; D016893:Carotid Stenosis / Q000188:drug therapy / Q000378:metabolism; D003327:Coronary Disease / Q000188:drug therapy / Q000378:metabolism; D003331:Coronary Vessels / Q000737:chemistry / Q000293:injuries / Q000378:metabolism; D006224:Cricetinae; D003459:Crystallins / Q000097:blood* / Q000737:chemistry / Q000494:pharmacology*; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D006490:Hemostatics / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000096:biosynthesis; D007457:Iodine Radioisotopes; D008970:Molecular Weight; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology; D013917:Thrombin / Q000494:pharmacology
D003459:Crystallins; D006360:Heat-Shock Proteins; D006490:Hemostatics; D007295:Inositol Phosphates; D007457:Iodine Radioisotopes; D013917:Thrombin; D002118:Calcium