| Abstract | Diamond-Blackfan anemia (DBA) is a congenital red-cell aplasia in which 25% of the patients have a mutation in the ribosomal protein (RP) S19 gene. It is not known how the RPS19 deficiency impairs erythropoiesis and proliferation of hematopoietic progenitors. To elucidate molecular mechanisms in RPS19-deficient DBA, we analyzed the effects of RPS19 deficiency on erythropoietin (EPO)-induced signal transduction, cell cycle, and apoptosis in RPS19-deficient TF-1 cells. We did not find any abnormality in EPO-induced signal transduction. However, RPS19-deficient TF-1 cells showed G0/G1 arrest (82% vs. 58%; p < .05) together with accumulation of p21 and p27. The fraction of apoptotic cells detected by Annexin V analysis also increased compared with control cells (13% vs. 3.1%; p < .05). Western blot analysis of apoptosis-related proteins showed that the level of bcl-2 and Bad was decreased and Bax was increased in RPS19-deficient TF-1 cells. Moreover, primary CD34-positive cells from DBA patients detected by Annexin V analysis also generated a higher number of apoptotic cells compared with normal CD34-positive cells during in vitro culture (38% vs. 8.9%; n = 5; p < .001). Finally, we show that although RPS19 silencing reduces EPO-induced development of erythroid progenitors expressing glycophorin A (GPA), RPS19 silencing in cells already expressing GPA does not affect GPA expression. These findings indicate that RPS19 deficiency causes apoptosis and accelerated loss of erythroid progenitors in RPS19-deficient DBA. |
| Authors | Koich Miyake, Taiju Utsugisawa, Johan Flygare, Thomas Kiefer, Isao Hamaguchi, Johan Richter, Stefan Karlsson
(Affiliation: Molecular Medicine and Gene Therapy, Lund University, BMC A12, 221 84, Lund, Sweden.)
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| Journal | Stem cells (Dayton, Ohio)
(Stem Cells)
Vol. 26
Issue 2
Pg. 323-9
(Feb 2008)
ISSN: 1549-4918 United States |
| PMID | 17962699
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
|
| Chemical References |
- Annexin A5
- Erythropoietin, Recombinant
- Glycophorin
- RNA, Small Interfering
- Receptors, Erythropoietin
- Ribosomal Proteins
- ribosomal protein S19
|
| Topics |
- Anemia, Diamond-Blackfan
(blood, genetics, pathology)
- Annexin A5
(metabolism)
- Apoptosis
- Cell Line
- Cell Proliferation
- Erythropoiesis
(drug effects, physiology)
- Erythropoietin, Recombinant
(pharmacology)
- Glycophorin
(metabolism)
- Hematopoietic Stem Cells
(drug effects, metabolism, pathology)
- Humans
- Models, Biological
- Mutation
- RNA, Small Interfering
(genetics)
- Receptors, Erythropoietin
(metabolism)
- Ribosomal Proteins
(antagonists & inhibitors, deficiency, genetics)
- Signal Transduction
(drug effects)
|
