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J Hematol Oncol. 2018 Feb 12;11(1):19. doi: 10.1186/s13045-018-0558-8.

SF3B1 deficiency impairs human erythropoiesis via activation of p53 pathway: implications for understanding of ineffective erythropoiesis in MDS.

Author information

1
Department of Hematology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, Henan, People's Republic of China.
2
Laboratory of Membrane Biology, New York Blood Center, New York, NY, 10065, USA.
3
Red Cell Physiology Laboratory, New York Blood Center, New York, NY, 10065, USA.
4
School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, 450001, People's Republic of China.
5
Department of Immunology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, 450008, People's Republic of China.
6
The State Key Laboratory of Medical Genetics and School of Life Sciences, Central South University, Changsha, 410078, People's Republic of China.
7
Laboratory of Complement Biology, New York Blood Center, New York, NY, 10065, USA.
8
Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, 45229, USA.
9
School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, 450001, People's Republic of China. lxchen@zzu.edu.cn.
10
Department of Hematology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, Henan, People's Republic of China. sunling6686@126.com.
11
Department of Hematology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, Henan, People's Republic of China. xan@nybc.org.
12
Laboratory of Membrane Biology, New York Blood Center, New York, NY, 10065, USA. xan@nybc.org.
13
School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, 450001, People's Republic of China. xan@nybc.org.

Abstract

BACKGROUND:

SF3B1 is a core component of splicing machinery. Mutations in SF3B1 are frequently found in myelodysplastic syndromes (MDS), particularly in patients with refractory anemia with ringed sideroblasts (RARS), characterized by isolated anemia. SF3B1 mutations have been implicated in the pathophysiology of RARS; however, the physiological function of SF3B1 in erythropoiesis remains unknown.

METHODS:

shRNA-mediated approach was used to knockdown SF3B1 in human CD34+ cells. The effects of SF3B1 knockdown on human erythroid cell differentiation, cell cycle, and apoptosis were assessed by flow cytometry. RNA-seq, qRT-PCR, and western blot analyses were used to define the mechanisms of phenotypes following knockdown of SF3B1.

RESULTS:

We document that SF3B1 knockdown in human CD34+ cells leads to increased apoptosis and cell cycle arrest of early-stage erythroid cells and generation of abnormally nucleated late-stage erythroblasts. RNA-seq analysis of SF3B1-knockdown erythroid progenitor CFU-E cells revealed altered splicing of an E3 ligase Makorin Ring Finger Protein 1 (MKRN1) and subsequent activation of p53 pathway. Importantly, ectopic expression of MKRN1 rescued SF3B1-knockdown-induced alterations. Decreased expression of genes involved in mitosis/cytokinesis pathway including polo-like kinase 1 (PLK1) was noted in SF3B1-knockdown polychromatic and orthochromatic erythroblasts comparing to control cells. Pharmacologic inhibition of PLK1 also led to generation of abnormally nucleated erythroblasts.

CONCLUSIONS:

These findings enabled us to identify novel roles for SF3B1 in human erythropoiesis and provided new insights into its role in regulating normal erythropoiesis. Furthermore, these findings have implications for improved understanding of ineffective erythropoiesis in MDS patients with SF3B1 mutations.

KEYWORDS:

Apoptosis; Human erythropoiesis; P53; SF3B1

PMID:
29433555
PMCID:
PMC5810112
DOI:
10.1186/s13045-018-0558-8
[Indexed for MEDLINE]
Free PMC Article

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