Molecular pathways of early CD105-positive erythroid cells as compared with CD34-positive common precursor cells by flow cytometric cell-sorting and gene expression profiling

S Machherndl-Spandl,M C Béné,S Suessner,H-U Klein,J Lauf,C Gabriel,A Weltermann,R Sylie,P Bettelheim,J Proell,M Danzer

doi:10.1038/bcj.2012.45

Abstract

Special attention has recently been drawn to the molecular network of different genes that are responsible for the development of erythroid cells. The aim of the present study was to establish in detail the immunophenotype of early erythroid cells and to compare the gene expression profile of freshly isolated early erythroid precursors with that of the CD34-positive (CD34+) compartment. Multiparameter flow cytometric analyses of human bone marrow mononuclear cell fractions (n=20) defined three distinct early erythroid stages. The gene expression profile of sorted early erythroid cells was analyzed by Affymetrix array technology. For 4524 genes, a differential regulation was found in CD105-positive erythroid cells as compared with the CD34+ progenitor compartment (2362 upregulated genes). A highly significant difference was observed in the expression level of genes involved in transcription, heme synthesis, iron and mitochondrial metabolism and transforming growth factor-β signaling. A comparison with recently published data showed over 1000 genes that as yet have not been reported to be upregulated in the early erythroid lineage. The gene expression level within distinct pathways could be illustrated directly by applying the Ingenuity software program. The results of gene expression analyses can be seen at the Gene Expression Omnibus repository.

Highlights

Erythropoietin transcription depends on such physiological processes as the regulation of transcriptional responses to hypoxia and involves signaling by transforming growth factor-b (TGF-b), which regulates the expression of the erythropoietin gene.[12,13]
This study investigated stage-specific changes in the expression level of genes, which are important regulators of early erythropoiesis
The discrimination between early erythroid cells and myeloid precursor cells as well as their exact characterization are of clinical significance, especially in such pathological conditions as myelodysplastic syndromes, in which flow cytometry (FCM) analyses are of growing diagnostic and prognostic relevance.[25,26,27,28,29]

Summary

Introduction

The molecular network of genes involved in the development of erythroid cells has begun to be better understood for the past few years.[1,2,3,4,5,6,7,8,9] The underlying molecular mechanism of erythroid cellular differentiation is a complex process, which is subject to a number of physiological conditions.[10,11,12,13,14,15,16,17] Most importantly, erythroid differentiation is regulated by the erythroid transcription factor globin transcription factor (GATA)-1, which represses GATA2 and PU.[1] and impacts on early and late differentiation.[18,19] At the terminal stage of differentiation, the erythroid program is defined by the genes that are still expressed. Erythropoietin transcription depends on such physiological processes as the regulation of transcriptional responses to hypoxia and involves signaling by transforming growth factor-b (TGF-b), which regulates the expression of the erythropoietin gene.[12,13]

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Conclusion