The genomic analysis of erythrocyte microRNA expression in sickle cell diseases.
BACKGROUND
Since mature erythrocytes are terminally differentiated cells without nuclei and organelles, it is commonly thought that they do not contain nucleic acids. In this study, we have re-examined this issue by analyzing the transcriptome of a purified population of human mature erythrocytes from individuals with normal hemoglobin (HbAA) and homozygous sickle cell disease (HbSS).


RESULTS
Using a combination of microarray analysis, real-time RT-PCR and Northern blots, we found that mature erythrocytes, while lacking ribosomal and large-sized RNAs, contain abundant and diverse microRNAs. MicroRNA expression of erythrocytes was different from that of reticulocytes and leukocytes, and contributed the majority of the microRNA expression in whole blood. When we used microRNA microarrays to analyze erythrocytes from HbAA and HbSS individuals, we noted a dramatic difference in their microRNA expression pattern. We found that miR-320 played an important role for the down-regulation of its target gene, CD71 during reticulocyte terminal differentiation. Further investigation revealed that poor expression of miR-320 in HbSS cells was associated with their defective downregulation CD71 during terminal differentiation.


CONCLUSIONS
In summary, we have discovered significant microRNA expression in human mature erythrocytes, which is dramatically altered in HbSS erythrocytes and their defect in terminal differentiation. Thus, the global analysis of microRNA expression in circulating erythrocytes can provide mechanistic insights into the disease phenotypes of erythrocyte diseases.
The Institute for Genome Sciences and Policy, Duke University School of Medicine, Durham, North Carolina, United States of America.
Shao-Yin
SY
Chen
Yulei
Y
Wang
Marilyn J
MJ
Telen
Jen-Tsan
JT
Chi
D000755:Anemia, Sickle Cell / Q000097:blood / Q000235:genetics*; D015703:Antigens, CD / Q000235:genetics; D001483:Base Sequence; D015152:Blotting, Northern; D017931:DNA Primers; D004912:Erythrocytes / Q000378:metabolism*; D020869:Gene Expression Profiling; D023281:Genomics; D006451:Hemoglobin, Sickle / Q000235:genetics; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D011990:Receptors, Transferrin / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
D015703:Antigens, CD; C068126:CD71 antigen; D017931:DNA Primers; D006451:Hemoglobin, Sickle; D035683:MicroRNAs; D011990:Receptors, Transferrin