Carbamylated darbepoetin derivative prevents endothelial progenitor cell damage with no effect on angiogenesis.
Erythropoietin (EPO) prevents cell apoptosis induced by oxidative stress. Carbamylated EPO maintains the tissue-protective activities of the unmodified EPO but does not stimulate erythropoiesis. This study evaluates whether carbamylated erythropoietin is as effective as recombinant human erythropoietin in protecting endothelial progenitor cells (EPCs) from apoptosis without stimulating erythropoiesis. Experiments were performed in an erythroid cell line (UT-7) and in human EPCs. Cell signals regulating proliferation and apoptosis (Jak-2, Akt, Erk1/2, NFkappaB and Stat-5) were measured by Western blotting. In human EPCs, cell senescence, apoptosis and proliferation were assessed by acidic beta-gal and measurement of telomere length, TUNEL and PCNA labeling, respectively. Angiogenesis was evaluated using the endothelial tube formation assay. In UT-7, carbamylated erythropoietin (C-darbe) induced phosphorylation of the anti-apoptotic Jak-2/Akt signal and, as opposed to recombinant human erythropoietin (darbe), did not produce a significant activation of cell proliferating signals. Darbe increased the percent of proliferating EPCs and promoted angiogenesis. By contrast, C-darbe failed to stimulate proliferation of EPCs. Both C-darbe and darbe equally reduced apoptosis and senescence. Thus, C-darbe protects EPCs from apoptosis and does not increase erythropoiesis.
Unidad de Investigación, Servicio de Nefrología, Hospital Universitario Reina Sofía, Avda. Menéndez Pidal S/N, Cordoba-14004, Spain. manuelr.ramirez.sspa@juntadeandalucia.es
Rafael
R
Ramirez
Julia
J
Carracedo
Sonia
S
Nogueras
Paula
P
Buendia
Ana
A
Merino
Sagrario
S
Cañadillas
Mariano
M
Rodríguez
Ciro
C
Tetta
Alejandro
A
Martin-Malo
Pedro
P
Aljama
D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D016922:Cellular Senescence; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D004921:Erythropoietin / Q000031:analogs & derivatives* / Q000494:pharmacology; D006801:Humans; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D016615:Telomere / Q000378:metabolism
D018809:Proliferating Cell Nuclear Antigen; C488171:carbamylated erythropoietin; D004921:Erythropoietin