RRC ID 64175
Author Lee TY, Lu WJ, Changou CA, Hsiung YC, Trang NTT, Lee CY, Chang TH, Jayakumar T, Hsieh CY, Yang CH, Chang CC, Chen RJ, Sheu JR, Lin KH.
Title Platelet autophagic machinery involved in thrombosis through a novel linkage of AMPK-MTOR to sphingolipid metabolism.
Journal Autophagy
Abstract Basal macroautophagy/autophagy has recently been found in anucleate platelets. Platelet autophagy is involved in platelet activation and thrombus formation. However, the mechanism underlying autophagy in anucleate platelets require further clarification. Our data revealed that LC3-II formation and SQSTM1/p62 degradation were noted in H2O2-activated human platelets, which could be blocked by 3-methyladenine and bafilomycin A1, indicating that platelet activation may cause platelet autophagy. AMPK phosphorylation and MTOR dephosphorylation were also detected, and block of AMPK activity by the AMPK inhibitor dorsomorphin could reverse SQSTM1 degradation and LC3-II formation. Moreover, autophagosome formation was observed through transmission electron microscopy and deconvolution microscopy. These findings suggest that platelet autophagy was induced partly through the AMPK-MTOR pathway. In addition, increased LC3-II expression occurred only in H2O2-treated Atg5f/f platelets, but not in H2O2-treated atg5-/- platelets, providing further evidence that platelet autophagy occurs during platelet activation. atg5-/- platelets also exhibited a lower aggregation in response to agonists, and platelet-specific atg5-/- mice exhibited delayed thrombus formation in mesenteric microvessles and decreased mortality rate due to pulmonary thrombosis. Notably, metabolic analysis revealed that sphingolipid metabolism is involved in platelet activation, as evidenced by observed several altered metabolites, which could be reversed by dorsomorphin. Therefore, platelet autophagy and platelet activation are positively correlated, partly through the interconnected network of sphingolipid metabolism. In conclusion, this study for the first time demonstrated that AMPK-MTOR signaling could regulate platelet autophagy. A novel linkage between AMPK-MTOR and sphingolipid metabolism in anucleate platelet autophagy was also identified: platelet autophagy and platelet activation are positively correlated.
Volume 17(12)
Pages 4141-4158
Published 2021-12-1
DOI 10.1080/15548627.2021.1904495
PMID 33749503
PMC PMC8726689
MeSH AMP-Activated Protein Kinases / metabolism Animals Autophagy* / physiology Blood Platelets / metabolism Chromatography, Liquid Hydrogen Peroxide Mice Phosphatidylinositol 3-Kinases / metabolism Sphingolipids TOR Serine-Threonine Kinases / metabolism Tandem Mass Spectrometry Thrombosis*
IF 9.77
Mice RBRC02975