MicroRNA-1 and -499 regulate differentiation and proliferation in human-derived cardiomyocyte progenitor cells.
OBJECTIVE
To improve regeneration of the injured myocardium, it is necessary to enhance the intrinsic capacity of the heart to regenerate itself and/or replace the damaged tissue by cell transplantation. Cardiomyocyte progenitor cells (CMPCs) are a promising cell population, easily expanded and efficiently differentiated into beating cardiomyocytes. Recently, several studies have demonstrated that microRNAs (miRNAs) are important for stem cell maintenance and differentiation via translational repression. We hypothesize that miRNAs are also involved in proliferation/differentiation of the human CMPCs in vitro.


RESULTS
Human fetal CMPCs were isolated, cultured, and efficiently differentiated into beating cardiomyocytes. miRNA expression profiling demonstrated that muscle-specific miR-1 and miR-499 were highly upregulated in differentiated cells. Transient transfection of miR-1 and -499 in CMPC reduced proliferation rate by 25% and 15%, respectively, and enhanced differentiation into cardiomyocytes in human CMPCs and embryonic stem cells, likely via the repression of histone deacetylase 4 or Sox6. Histone deacetylase 4 and Sox6 protein levels were reduced, and small interference RNA (siRNA)-mediated knockdown of Sox6 strongly induced myogenic differentiation.


CONCLUSIONS
miRNAs regulate the proliferation of human CMPC and their differentiation into cardiomyocytes. By modulating miR-1 and -499 expression levels, human CMPC function can be altered and differentiation directed, thereby enhancing cardiomyogenic differentiation.
Sluijter
Joost P G
JP
University Medical Center Utrecht, Department of Cardiology, Division of Heart and Lungs, Heidelberglaan 100, Utrecht, The Netherlands. j.sluijter@umcutrecht.nl
van Mil
Alain
A
van Vliet
Patrick
P
Metz
Corina H G
CH
Liu
Jia
J
Doevendans
Pieter A
PA
Goumans
Marie-José
MJ
D002454:Cell Differentiation / Q000235:genetics*; D049109:Cell Proliferation; D002478:Cells, Cultured; D053686:Fetal Stem Cells / Q000378:metabolism*; D020869:Gene Expression Profiling / Q000379:methods; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D024510:Muscle Development / Q000235:genetics*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D034622:RNA Interference; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D055755:SOXD Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection; D015854:Up-Regulation
C544547:MIRN1 microRNA, human; C548683:MIRN499 microRNA, human; D035683:MicroRNAs; D012097:Repressor Proteins; C486270:SOX6 protein, human; D055755:SOXD Transcription Factors; C400300:HDAC4 protein, human; D006655:Histone Deacetylases