title: All-trans retinoic acid prevents apoptosis of human marrow CD34+ cells deprived of haematopoietic growth factors.
abstract: The regulation of apoptosis plays a key role in haematopoiesis. It has been demonstrated that haematopoietic progenitor cells progressively undergo apoptotic cell death in the absence of appropriate growth factors. We studied the effects of pharmacological doses of all-transretinoic acid (ATRA) on the apoptosis of human adult marrow CD34+ progenitor cells cultured for 7 d in a serum-free medium. We quantified CD34+ cells, clonogenic progenitors and 5 week colony-forming cells (CFC) before and after ATRA exposure. Moreover, we defined the apoptotic status of the CD34+ cell fraction by analysis of phosphatidylserine externalization (using annexin V), the relative membrane permeability to 7-aminoactinomycin D (7AAD) and the mitochondrial membrane potential [using 3,3'-dihexyloxacarbocyanine iodide, DiOC6(3)]. In the drastic experimental conditions used, a decrease in viable CD34+ cells, granulocyte-macrophage colony-forming units (CFU-GM), erythroid burst-forming units (BFU-E) and 5 week CFC were observed. Exposure to ATRA partially prevented the decrease in viable CD34+, without a concomitant effect on the clonogenic and more immature progenitors. ATRA-treated CD34+ cells displayed changes in apoptotic status compared with control cultures, particularly in lower annexin V-binding. These results were confirmed using 7AAD and DiOC6(3). Our results demonstrate that ATRA exerts a protective effect on CD34+ cells exposed to such apoptotic stress.
authors.affiliation: EA-3249 'Cellules Hématopoïétiques, Hémostase et Greffe' Faculty of Medicine, University Hospital, Tours, France. olivier.herault@med.univ-tours.fr
authors.forename: Olivier
authors.initials: O
authors.lastname: Herault
authors.forename: Jorge
authors.initials: J
authors.lastname: Domenech
authors.forename: Marie Therese
authors.initials: MT
authors.lastname: Georget
authors.forename: Nathalie
authors.initials: N
authors.lastname: Clement
authors.forename: Philippe
authors.initials: P
authors.lastname: Colombat
authors.forename: Christian
authors.initials: C
authors.lastname: Binet
mesh_terms: D017302:Annexins / Q000378:metabolism; D018952:Antigens, CD34; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D001854:Bone Marrow Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D002470:Cell Survival; D002478:Cells, Cultured; D002999:Clone Cells; D016895:Culture Media, Serum-Free; D006801:Humans; D011485:Protein Binding; D013997:Time Factors; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D017302:Annexins; D018952:Antigens, CD34; D000970:Antineoplastic Agents; D016895:Culture Media, Serum-Free; D014212:Tretinoin