title: Platelet bioenergetic screen in sickle cell patients reveals mitochondrial complex V inhibition, which contributes to platelet activation.
abstract: Bioenergetic dysfunction, although central to the pathogenesis of numerous diseases, remains uncharacterized in many patient populations because of the invasiveness of obtaining tissue for mitochondrial studies. Although platelets are an accessible source of mitochondria, the role of bioenergetics in regulating platelet function remains unclear. Herein, we validate extracellular flux analysis in human platelets and use this technique to screen for mitochondrial dysfunction in sickle cell disease (SCD) patients, a population with aberrant platelet activation of an unknown mechanism and in which mitochondrial function has never been assessed. We identify a bioenergetic alteration in SCD patients characterized by deficient complex V activity, leading to decreased mitochondrial respiration, membrane hyperpolarization, and augmented oxidant production compared with healthy subjects. This dysfunction correlates with platelet activation and hemolysis in vivo and can be recapitulated in vitro by exposing healthy platelets to hemoglobin or a complex V inhibitor. Further, reproduction of this dysfunction in vitro activates healthy platelets, an effect prevented by attenuation of mitochondrial hyperpolarization or by scavenging mitochondrial oxidants. These data identify bioenergetic dysfunction in SCD patients for the first time and establish mitochondrial hyperpolarization and oxidant generation as potential pathogenic mechanism in SCD as well as a modulator of healthy platelet function.
authors.affiliation: Vascular Medicine Institute and.
authors.forename: Nayra
authors.initials: N
authors.lastname: Cardenes
authors.forename: Catherine
authors.initials: C
authors.lastname: Corey
authors.forename: Lisa
authors.initials: L
authors.lastname: Geary
authors.forename: Shilpa
authors.initials: S
authors.lastname: Jain
authors.forename: Sergey
authors.initials: S
authors.lastname: Zharikov
authors.forename: Suchitra
authors.initials: S
authors.lastname: Barge
authors.forename: Enrico M
authors.initials: EM
authors.lastname: Novelli
authors.forename: Sruti
authors.initials: S
authors.lastname: Shiva
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000328:Adult; D000755:Anemia, Sickle Cell / Q000378:metabolism*; D001792:Blood Platelets / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D016022:Case-Control Studies; D005260:Female; D006461:Hemolysis; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism*; D025261:Mitochondrial Proton-Translocating ATPases; D010101:Oxygen Consumption; D015539:Platelet Activation; D010974:Platelet Aggregation; D017382:Reactive Oxygen Species / Q000378:metabolism; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D017382:Reactive Oxygen Species; D000251:Adenosine Triphosphatases; D025261:Mitochondrial Proton-Translocating ATPases; C020439:oligomycin sensitivity-conferring protein