MIR-23A microRNA cluster inhibits B-cell development

Kong, Kimi Y.; Owens, Kristin S.; Rogers, Jason H.; Mullenix, Jason; Velu, Chinavenmeni S.; Grimes, H. Leighton; Dahl, Richard

doi:10.1016/j.exphem.2010.04.004

« Previous Next »Experimental Hematology
Volume 38, Issue 8 , Pages 629-640.e1, August 2010

MIR-23A microRNA cluster inhibits B-cell development

Kimi Y. Kong
- Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM., USA
- Drs. Kong, Owens, and Rogers contributed equally to this work.
Kristin S. Owens
- Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM., USA
- Drs. Kong, Owens, and Rogers contributed equally to this work.
Jason H. Rogers
- Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM., USA
- Drs. Kong, Owens, and Rogers contributed equally to this work.
Jason Mullenix
- Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM., USA
Chinavenmeni S. Velu
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH., USA
H. Leighton Grimes
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH., USA
Richard Dahl
- Cancer Research and Treatment Center, University of New Mexico, Albuquerque, NM., USA
- Department of Internal Medicine, Health Sciences Center, University of New Mexico, Albuquerque, NM., USA
- Offprint requests to: Richard Dahl, Ph.D., Indiana University School of Medicine South Bend, 1234 Notre Dame Avenue, South Bend, IN 46617

Received 13 February 2010; received in revised form 7 April 2010; accepted 8 April 2010. published online 16 April 2010.

Objective

The transcription factor PU.1 (encoded by Sfpi1) promotes myeloid differentiation, but it is unclear what downstream genes are involved. Micro RNAs (miRNAs) are a class of small RNAs that regulate many cellular pathways, including proliferation, survival, and differentiation. The objective of this study was to identify miRNAs downstream of PU.1 that regulate hematopoietic development.

Materials and Methods

miRNAs that change expression in a PU.1-inducible cell line were identified with microarrays. The promoter for an miRNA cluster upregulated by PU.1 induction was analyzed for PU.1 binding by electrophoretic mobility shift and chromatin immunoprecipitation assays. Retroviral transduction of hematopoietic progenitors was performed to evaluate the effect of miRNA expression on hematopoietic development in vitro and in vivo.

Results

We identified an miRNA cluster whose pri-transcript is regulated by PU.1. The pri-miRNA encodes three mature miRNAs: miR-23a, miR-27a, and miR-24-2. Each miRNA is more abundant in myeloid cells compared to lymphoid cells. When hematopoietic progenitors expressing the 23a cluster miRNAs were cultured in B-cell−promoting conditions, we observed a dramatic decrease in B lymphopoiesis and an increase in myelopoiesis compared to control cultures. In vivo, hematopoietic progenitors expressing the miR-23a cluster generate reduced numbers of B cells compared to control cells.

Conclusions

The miR-23a cluster is a downstream target of PU.1 involved in antagonizing lymphoid cell fate acquisition. Although miRNAs have been identified downstream of PU.1 in mediating development of monocytes and granulocytes, the 23a cluster is the first downstream miRNA target implicated in regulating development of myeloid vs lymphoid cells.