Steroid resistance in Diamond Blackfan anemia associates with p57Kip2 dysregulation in erythroid progenitors
Ryan J. Ashley, Hongxia Yan, Nan Wang, John Hale, Brian M. Dulmovits, Julien Papoin, Meagan E. Olive, Namrata D. Udeshi, Steven A. Carr, Adrianna Vlachos, Jeffrey M. Lipton, Lydie Da Costa, Christopher Hillyer, Sandrina Kinet, Naomi Taylor, Narla Mohandas, Anupama Narla, Lionel Blanc
Ryan J. Ashley, Hongxia Yan, Nan Wang, John Hale, Brian M. Dulmovits, Julien Papoin, Meagan E. Olive, Namrata D. Udeshi, Steven A. Carr, Adrianna Vlachos, Jeffrey M. Lipton, Lydie Da Costa, Christopher Hillyer, Sandrina Kinet, Naomi Taylor, Narla Mohandas, Anupama Narla, Lionel Blanc
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Research Article Development Hematology

Steroid resistance in Diamond Blackfan anemia associates with p57Kip2 dysregulation in erythroid progenitors

Abstract

Despite the effective clinical use of steroids for the treatment of Diamond Blackfan anemia (DBA), the mechanisms through which glucocorticoids regulate human erythropoiesis remain poorly understood. We report that the sensitivity of erythroid differentiation to dexamethasone is dependent on the developmental origin of human CD34+ progenitor cells, specifically increasing the expansion of CD34+ progenitors from peripheral blood (PB) but not cord blood (CB). Dexamethasone treatment of erythroid-differentiated PB, but not CB, CD34+ progenitors resulted in the expansion of a newly defined CD34+CD36+CD71hiCD105med immature colony-forming unit–erythroid (CFU-E) population. Furthermore, proteomics analyses revealed the induction of distinct proteins in dexamethasone-treated PB and CB erythroid progenitors. Dexamethasone treatment of PB progenitors resulted in the specific upregulation of p57Kip2, a Cip/Kip cyclin–dependent kinase inhibitor, and we identified this induction as critical; shRNA-mediated downregulation of p57Kip2, but not the related p27Kip1, significantly attenuated the impact of dexamethasone on erythroid differentiation and inhibited the expansion of the immature CFU-E subset. Notably, in the context of DBA, we found that steroid resistance was associated with dysregulated p57Kip2 expression. Altogether, these data identify a unique glucocorticoid-responsive human erythroid progenitor and provide new insights into glucocorticoid-based therapeutic strategies for the treatment of patients with DBA.

Authors

Ryan J. Ashley, Hongxia Yan, Nan Wang, John Hale, Brian M. Dulmovits, Julien Papoin, Meagan E. Olive, Namrata D. Udeshi, Steven A. Carr, Adrianna Vlachos, Jeffrey M. Lipton, Lydie Da Costa, Christopher Hillyer, Sandrina Kinet, Naomi Taylor, Narla Mohandas, Anupama Narla, Lionel Blanc

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Figure 7

Dexamethasone increases p57Kip2 levels in Epo-induced, BM-derived progenitors, expanding the immature CD105med CFU-E subset.

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Dexamethasone increases p57Kip2 levels in Epo-induced, BM-derived progen...
(A) BM CD34+ progenitors were differentiated in the absence (open circles) or presence (solid circles) of dexamethasone, and total cell numbers on day 14 are presented (n = 5 independent experiments). Data represent the mean ± SEM. *P < 0.05, by 2-tailed Student’s t test. (B) Representative histograms of CD105 expression in BM-derived CD34+ cells differentiated in the absence (black) or presence (red) of dexamethasone on day 4 are shown, and the percentages of CD105med cells are indicated. (C) Expression of p57Kip2 and GAPDH in purified BM-derived and CB-derived mature CFU-Es, generated in the absence or presence of dexamethasone, was evaluated by Western blotting (blots from 1 of 3 independent experiments are shown).