title: Bcl-xL and Mcl-1 are involved in prevention of in vitro apoptosis in rat late-stage erythroblasts derived from bone marrow.
abstract: Apoptosis controls erythroid homeostasis by balancing survival and death of erythroid cells. The mitochondrial pathway of apoptosis involves regulation of apoptotic events caused by the Bcl-2 family proteins, including the anti-apoptotic and pro-apoptotic members. However, little has been reported on the role of the anti-apoptotic Bcl-2 family members in rat late-stage erythroblasts that are no longer erythropoietin (EPO)-dependent. In the present study, to investigate this we analyzed changes in apoptosis-related factors that occurred in vitro. EPO stimulation resulted in reduced apoptotic cell death of the late-stage erythroblasts accompanied by decreased caspase-3 and caspase-9 activities, which is indicative of the induction of apoptosis through the mitochondrial pathway. Analysis of mRNA expression of the Bcl-2 family proteins demonstrated that EPO stimulation up-regulated the Bcl-xL mRNA, resulting in decreases in the mRNA ratios of Bak, Bax, and Bad to Bcl-xL. Also, the mRNA ratios of Bak and Noxa to Mcl-1 were decreased, mainly due to up-regulation of Mcl-1 mRNA. These results showed a close association between reduced apoptotic cell death and increased mRNA levels of Bcl-xL and Mcl-1 in the presence of EPO. Thus, the present study suggests that Bcl-xL may be an important anti-apoptotic factor of rat late-stage erythroblasts as has been reported in murine erythroblasts. Moreover, the results also indicate the possibility that Mcl-1 may act on the rat late-stage erythroblasts as an anti-apoptotic factor.
authors.affiliation: Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 3-1-98 Kasugade-Naka, Komohana-ku, Osaka, 554-8558, Japan. asanot2@sc.sumitomo-chem.co.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Asano
authors.forename: Satoki
authors.initials: S
authors.lastname: Fukunaga
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Deguchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kawamura
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Inaba
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001854:Bone Marrow Cells / Q000166:cytology; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D053938:DNA Fragmentation; D004900:Erythroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004921:Erythropoietin / Q000494:pharmacology*; D005260:Female; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D051020:bcl-X Protein / Q000235:genetics*
chemical_list: C494813:Bcl2l1 protein, rat; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D051020:bcl-X Protein; D004921:Erythropoietin; D053148:Caspase 3; D053453:Caspase 9