Article | Published:

Myelodysplastic syndrome

Uncoupling of CD71 shedding with mitochondrial clearance in reticulocytes in a subset of myelodysplastic syndromes


Reticulocytes shed CD71 from the cell membrane and eliminate mitochondria during terminal maturation, but it is unknown whether these two events are coordinated. We demonstrate that timely removal of CD71 is coupled with mitochondrial clearance, which can be disrupted by null mutation of immediate early response gene X-1 (IEX-1), leading to generation of aberrant CD71-positive and mitochondria-negative (CD71+Mito) reticulocytes. CD71+Mito reticulocytes were also present in a subset of patients with myelodysplastic syndromes (MDS) in direct proportion to reduced mitochondrial membrane potential (∆ψm). Mitochondrial abnormality caused by either IEX-1 deficiency or agents that dissipate ∆ψm could trigger premature clearance of mitochondria in reticulocytes. Premature clearance of mitochondria or addition of anti-oxidants lowered intracellular reactive oxygen species (ROS) that in turn hindered CD71 shedding and reticulocyte maturation. In contrast, introduction of ROS accelerated CD71 shedding via release of exosomes that contained a high proportion of Fe3+ over Fe2+, suggesting dual functions of CD71 shedding both in removal of toxic Fe3+ from reticulocytes and in limiting importation of Fe3+ into the cells. These observations emphasize the coordination of mitochondrial and CD71 clearance in erythroid terminal maturation and offer new insights into a role for mitochondrial degeneration in the pathogenesis of some MDS-associated anemia.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    Heaney ML, Golde DW. Myelodysplasia. N Engl J Med. 1999;340:1649–60. 5/27/1999

  2. 2.

    Hofmann WK, de Vos S, Komor M, Hoelzer D, Wachsman W, Koeffler HP. Characterization of gene expression of CD34+cells from normal and myelodysplastic bone marrow. Blood. 2002;100:3553–60. 11/15/2002

  3. 3.

    Steensma DP, Neiger JD, Porcher JC, Keats JJ, Bergsagel PL, Dennis TR, et al. Rearrangements and amplification of IER3 (IEX-1) represent a novel and recurrent molecular abnormality in myelodysplastic syndromes. Cancer Res. 2009;69:7518–23. 10/1/2009

  4. 4.

    Prall WC, Czibere A, Grall F, Spentzos D, Steidl U, Giagounidis AA, et al. Differential gene expression of bone marrow-derived CD34+cells is associated with survival of patients suffering from myelodysplastic syndrome. Int J Hematol. 2009;89:173–87. 3/2009

  5. 5.

    Shen L, Zhi L, Hu W, Wu MX. IEX-1 targets mitochondrial F1Fo-ATPase inhibitor for degradation. Cell Death Differ. 2009;16:603–12. 4/2009

  6. 6.

    Zhang Q, Zhou C, Hamblin MR, Wu MX. Low-level laser therapy effectively prevents secondary brain injury induced by immediate early responsive gene X-1 deficiency. J Cereb Blood Flow Metab. 2014;34:1391–401. 8/2014

  7. 7.

    Ramsey H, Zhang Q, Brown DE, Steensma DP, Lin CP, Wu MX. Stress-induced hematopoietic failure in the absence of immediate early response gene X-1 (IEX-1, IER3). Haematologica. 2014;99:282–91. 2/2014

  8. 8.

    Zhang Q, Dong T, Li P, Wu MX. Noninvasive low-level laser therapy for thrombocytopenia. Sci Transl Med. 2016;8:349ra101. 7/27/2016

  9. 9.

    Holm TM, Braun A, Trigatti BL, Brugnara C, Sakamoto M, Krieger M, et al. Failure of red blood cell maturation in mice with defects in the high-density lipoprotein receptor SR-BI. Blood. 2002;99:1817–24. 3/1/2002

  10. 10.

    Kundu M, Lindsten T, Yang CY, Wu J, Zhao F, Zhang J, et al. Ulk1 plays a critical role in the autophagic clearance of mitochondria and ribosomes during reticulocyte maturation. Blood. 2008;112:1493–502. 8/15/2008

  11. 11.

    Sandoval H, Thiagarajan P, Dasgupta SK, Schumacher A, Prchal JT, Chen M, et al. Essential role for Nix in autophagic maturation of erythroid cells. Nature. 2008;454:232–5. 7/10/2008

  12. 12.

    Geminard C, de Gassart A, Vidal M. Reticulocyte maturation: mitoptosis and exosome release. Biocell. 2002;26:205–15. 8/2002

  13. 13.

    Kanias T, Acker JP. Biopreservation of red blood cells-the struggle with hemoglobin oxidation. FEBS J. 2010;277:343–56. 1/2010

  14. 14.

    Johnstone RM, Adam M, Pan BT. The fate of the transferrin receptor during maturation of sheep reticulocytes in vitro. Can J Biochem Cell Biol. 1984;62:1246–54. 11/1984

  15. 15.

    Koury MJ, Koury ST, Kopsombut P, Bondurant MC. In vitro maturation of nascent reticulocytes to erythrocytes. Blood. 2005;105:2168–74. 3/1/2005

  16. 16.

    Gibbings DJ, Ciaudo C, Erhardt M, Voinnet O. Multivesicular bodies associate with components of miRNA effector complexes and modulate miRNA activity. Nat Cell Biol. 2009;11:1143–9. 9/2009

  17. 17.

    Socolovsky M, Nam H, Fleming MD, Haase VH, Brugnara C, Lodish HF. Ineffective erythropoiesis in Stat5a(-/-)5b(-/-) mice due to decreased survival of early erythroblasts. Blood. 2001;98:3261–73. 12/1/2001

  18. 18.

    Liu J, Guo X, Mohandas N, Chasis JA, An X. Membrane remodeling during reticulocyte maturation. Blood. 2010;115:2021–7. 3/11/2010

  19. 19.

    Campanella M, Casswell E, Chong S, Farah Z, Wieckowski MR, Abramov AY, et al. Regulation of mitochondrial structure and function by the F1Fo-ATPase inhibitor protein, IF1. Cell Metab. 2008;8:13–25. 7/2008

  20. 20.

    Ramsey H, Zhang Q, Wu MX. Mitoquinone restores platelet production in irradiation-induced thrombocytopenia. Platelets. 2015;26:459–66. 2015

  21. 21.

    Benz R, McLaughlin S. The molecular mechanism of action of the proton ionophore FCCP (carbonylcyanide p-trifluoromethoxyphenylhydrazone). Biophys J. 1983;41:381–98. 3/1983

  22. 22.

    Blommaart EF, Krause U, Schellens JP, Vreeling-Sindelarova H, Meijer AJ. The phosphatidylinositol 3-kinase inhibitors wortmannin and LY294002 inhibit autophagy in isolated rat hepatocytes. Eur J Biochem. 1997;243:240–6. 1/15/1997

  23. 23.

    Griffiths RE, Kupzig S, Cogan N, Mankelow TJ, Betin VM, Trakarnsanga K, et al. Maturing reticulocytes internalize plasma membrane in glycophorin A-containing vesicles that fuse with autophagosomes before exocytosis. Blood. 2012;119:6296–306. 6/28/2012

  24. 24.

    Savina A, Furlan M, Vidal M, Colombo MI. Exosome release is regulated by a calcium-dependent mechanism in K562 cells. J Biol Chem. 2003;278:20083–90. 5/30/2003

  25. 25.

    Blanc L, Liu J, Vidal M, Chasis JA, An X, Mohandas N. The water channel aquaporin-1 partitions into exosomes during reticulocyte maturation: implication for the regulation of cell volume. Blood. 2009;114:3928–34. Oct 29

  26. 26.

    Richardson DR, Ponka P, Vyoral D. Distribution of iron in reticulocytes after inhibition of heme synthesis with succinylacetone: examination of the intermediates involved in iron metabolism. Blood. 1996;87:3477–88. Apr 15

  27. 27.

    Harding CV, Heuser JE, Stahl PD. Exosomes: looking back three decades and into the future. J Cell Biol. 2013;200:367–71. 2/18/2013

  28. 28.

    Ohgami RS, Campagna DR, Greer EL, Antiochos B, McDonald A, Chen J, et al. Identification of a ferrireductase required for efficient transferrin-dependent iron uptake in erythroid cells. Nat Genet. 2005;37:1264–9. Nov

  29. 29.

    Canonne-Hergaux F, Levy JE, Fleming MD, Montross LK, Andrews NC, Gros P. Expression of the DMT1 (NRAMP2/DCT1) iron transporter in mice with genetic iron overload disorders. Blood. 2001;97:1138–40. Feb 15

  30. 30.

    Chiu DT, Liu TZ. Free radical and oxidative damage in human blood cells. J Biomed Sci. 1997;4:256–9. 1997

  31. 31.

    Cazzola M, Invernizzi R, Bergamaschi G, Levi S, Corsi B, Travaglino E, et al. Mitochondrial ferritin expression in erythroid cells from patients with sideroblastic anemia. Blood. 2003;101:1996–2000. Mar 1

  32. 32.

    Cuijpers ML, Raymakers RA, Mackenzie MA, de Witte TJ, Swinkels DW. Recent advances in the understanding of iron overload in sideroblastic myelodysplastic syndrome. Br J Haematol. 2010;149:322–33. May

  33. 33.

    Fontenay M, Cathelin S, Amiot M, Gyan E, Solary E. Mitochondria in hematopoiesis and hematological diseases. Oncogene. 2006;25:4757–67. 8/7/2006

  34. 34.

    Schweers RL, Zhang J, Randall MS, Loyd MR, Li W, Dorsey FC, et al. NIX is required for programmed mitochondrial clearance during reticulocyte maturation. Proc Natl Acad Sci USA. 2007;104:19500–5. 12/4/2007

  35. 35.

    Mortensen M, Ferguson DJ, Edelmann M, Kessler B, Morten KJ, Komatsu M, et al. Loss of autophagy in erythroid cells leads to defective removal of mitochondria and severe anemia in vivo. Proc Natl Acad Sci USA. 2010;107:832–7. 1/12/2010

  36. 36.

    Ahlqvist KJ, Leoncini S, Pecorelli A, Wortmann SB, Ahola S, Forsstrom S, et al. MtDNA mutagenesis impairs elimination of mitochondria during erythroid maturation leading to enhanced erythrocyte destruction. Nat Commun. 2015;6:6494. 3/9/2015

  37. 37.

    van de Loosdrecht AA, Brada SJ, Blom NR, Hendriks DW, Smit JW, van den BE, et al. Mitochondrial disruption and limited apoptosis of erythroblasts are associated with high risk myelodysplasia. An ultrastructural analysis. Leuk Res. 2001;25:385–93. 5/2001

  38. 38.

    Berger G, Hunault-Berger M, Rachieru P, Fontenay-Roupie M, Baranger L, Ifrah N, et al. Increased apoptosis in mononucleated cells but not in CD34+cells in blastic forms of myelodysplastic syndromes. Hematol J. 2001;2:87–96. 2001

  39. 39.

    Matthes TW, Meyer G, Samii K, Beris P. Increased apoptosis in acquired sideroblastic anaemia. Br J Haematol. 2000;111:843–52. 12/2000

  40. 40.

    Lin CW, Manshouri T, Jilani I, Neuberg D, Patel K, Kantarjian H, et al. Proliferation and apoptosis in acute and chronic leukemias and myelodysplastic syndrome. Leuk Res. 2002;26:551–9. 6/2002

  41. 41.

    Houwerzijl EJ, Pol HW, Blom NR, van der Want JJ, de Wolf JT, Vellenga E. Erythroid precursors from patients with low-risk myelodysplasia demonstrate ultrastructural features of enhanced autophagy of mitochondria. Leukemia. 2009;23:886–91. 5/2009

Download references


We thank the staff at the photopathology core at Wellman Center for Photomedicine for FACS and electron microscopy assistance. This research was supported in part by the National Institute of Health (NIH) grant CA158756 and Wellman Department fund to M.X.W., the Edward P. Evans Foundation for research in MDS to D.P.S., and a Bullock-Wellman postdoctoral fellowship to Q.Z.

Author contributions

Q.Z. designed and performed the experiments, analyzed the data, and wrote the manuscript; D.P.S. and J.Y. collected MDS samples, analyzed the data, and revised the manuscript; T.D. performed experiments; M.X.W. designed the experiments, analyzed the data, supervised the overall project, and wrote the manuscript.

Author information

Correspondence to Mei X. Wu.

Ethics declarations

Conflict of interest

The authors declare that they have no conflict of interest.

Electronic supplementary material

Supplementary methods and figures

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark
Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5