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Platelet senescence and phosphatidylserine exposure
Author(s) -
Dasgupta Swapan Kumar,
Argaiz Eduardo Rios,
Mercado Jose Emmanel Chedid,
Maul Hector Omar Elizondo,
Garza Jorge,
Enriquez Ana Bety,
AbdelMonem Hanan,
Prakasam Anthony,
Andreeff Michael,
Thiagarajan Perumal
Publication year - 2010
Publication title -
transfusion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.045
H-Index - 132
eISSN - 1537-2995
pISSN - 0041-1132
DOI - 10.1111/j.1537-2995.2010.02676.x
Subject(s) - phosphatidylserine , cytochrome c , apoptosis , caspase , microbiology and biotechnology , chemistry , mitochondrion , biochemistry , biology , programmed cell death , phospholipid , membrane
BACKGROUND: The exposure of phosphatidylserine occurs during platelet (PLT) activation and during in vitro storage. Phosphatidylserine exposure also occurs during apoptosis after the release of mitochondrial cytochrome c . We have examined the role of cytochrome c release, mitochondrial membrane potential (ΔΨm), and cyclophilin D (CypD) in phosphatidylserine exposure due to activation and storage. STUDY DESIGN AND METHODS: The exposure of phosphatidylserine and the loss of ΔΨm were determined in a flow cytometer using fluorescein isothiocyanate–lactadherin and JC‐1, a lipophilic cationic reporter dye. The role of CypD was determined with cyclosporin A and CypD‐deficient murine PLTs. Cytochrome c ‐induced caspase‐3 and Rho‐associated kinase I (ROCK1) activation were determined by immunoblotting and using their inhibitors. RESULTS: Collagen‐ and thrombin‐induced exposure of phosphatidylserine was accompanied by a decrease in ΔΨm. Cyclosporin A inhibited the phosphatidylserine exposure and the loss of ΔΨm. CypD −/− mice had decreased loss of ΔΨm and impaired phosphatidylserine exposure. Collagen and thrombin did not induce the release of cytochrome c nor the activation of caspase‐3 and ROCK1. In contrast, in PLTs stored for more than 5 days, the phosphatidylserine exposure was associated with cytochrome c –induced caspase‐3 and ROCK1 activation. ABT737, a BH3 mimetic that induces mitochondrial pathway of apoptosis, induced cytochrome c release and activation of caspase‐3 and ROCK1 and phosphatidylserine exposure independent of CypD. CONCLUSION: These results show that in stored PLTs cytochrome c release and the subsequent activation of caspase‐3 and ROCK1 mediate phosphatidylserine exposure and it is distinct from activation‐induced phosphatidylserine exposure.