1. Impact of Cyclin-Dependent Kinase CDK4 Inhibition on Eryptosis
- Author
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Mehrdad Ghashghaeinia, Adrian Lupescu, Anand Rotte, Rosi Bissinger, Florian Lang, Christine Zelenak, Elisabeth Lang, Matthias Eberhard, and Syed M. Qadri
- Subjects
Programmed cell death ,Erythrocytes ,CDK4 ,Cell Survival ,Physiology ,Cell ,Eryptosis ,Apoptosis ,Phosphatidylserines ,Biology ,600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit ,lcsh:Physiology ,Cell membrane ,lcsh:Biochemistry ,chemistry.chemical_compound ,tert-Butylhydroperoxide ,Cyclin-dependent kinase ,medicine ,Cell shrinkage ,Humans ,lcsh:QD415-436 ,Protein Kinase Inhibitors ,lcsh:QP1-981 ,Cell growth ,Cyclin-dependent kinase 4 ,Cyclin-Dependent Kinase 4 ,Phosphatidylserine ,Molecular biology ,Cell biology ,medicine.anatomical_structure ,chemistry ,biology.protein ,Calcium - Abstract
Background/Aims: The cyclin-dependent kinase 4 (CDK4) participates in the regulation of apoptosis of nucleated cells by altering transcriptional regulation of genes governing cell proliferation and cell death. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine (PS) exposure at the cell surface. As mature erythrocytes lack nuclei, acute stimulation of eryptosis cannot result from altered gene expression. Eryptosis is triggered by isotonic cell shrinkage following Cl- removal (replacement with the impermeant organic anion gluconate) or by oxidative stress (exposure to 0.3 mM tertbutyl-hydroperoxide [tBOOH]). The present study explored whether CDK4 is expressed in erythrocytes and whether the CDK4 inhibitors II (NSC625987) and III (ryuvidine) influence eryptosis. Methods: Western blotting was utilized for determination of the presence of CDK4 protein in human erythrocytes, and FACS analysis to determine Fluo3 fluorescence (reflecting cytosolic Ca2+), annexin-V-binding (reflecting PS-exposure) and forward scatter (reflecting cell volume). Results: CDK4 protein was present in human erythrocytes. Cl- removal was followed by decrease of forward scatter and increase of both annexin-V-binding and Fluo3 fluorescence, an effect significantly curtailed by CDK4 inhibitors II and III. Furthermore, CDK4 inhibition blunted enhanced PS-exposure elicited by tBOOH treatment. Conclusions: The present observations disclose the presence of CDK4 protein in human erythrocytes and the suppression of suicidal erythrocyte death by pharmacological inhibition of CDK4.
- Published
- 2015