title: A phenotypic screen to identify hypertrophy-modulating microRNAs in primary cardiomyocytes.
abstract: MicroRNAs (miRNAs) are small non-coding RNAs that control expression of complementary target mRNAs. A growing number of miRNAs has been implicated in the pathogenesis of cardiac diseases, mostly based not on functional data, but on the observation that they are dysregulated in diseased myocardium. Consequently, our knowledge regarding a potential cardiac role of the majority of miRNAs is limited. Here, we report the development of an assay format that allows the simultaneous analysis of several hundred molecules with regard to their phenotypic effect on primary rat cardiomyocytes. Using automated microscopy and an edge detection algorithm, this assay achieved high reproducibility and a robust assessment of cardiomyocyte size as a key parameter. Screening a library of synthetic miRNAs revealed several miRNAs previously not recognized as pro- or anti-hypertrophic. Out of these, we selected nine miRNAs and confirmed the pro-hypertrophic potential of miR-22, miR-30c, miR-30d, miR-212, miR-365 and the anti-hypertrophic potential of miR-27a, miR-27b and miR-133a. Quantitative analysis of the expression level of pro-hypertrophic miRNAs in primary cardiomyocytes indicated a rather low level of correlation of the phenotypic effects of individual miRNAs and their expression level. This assay allows the automated determination of cell size in primary cardiomyocytes and permitted the identification of a set of miRNAs capable of regulating cardiomyocyte hypertrophy. Elucidating their mechanism of action should provide insight into mechanisms underlying the cardiomyocyte hypertrophic response. This article is part of a Special Issue entitled 'Possible Editorial'.
authors.affiliation: Institut für Pharmakologie und Toxikologie, Technische Universität München (TUM), Munich, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Jentzsch
authors.forename: Simon
authors.initials: S
authors.lastname: Leierseder
authors.forename: Xavier
authors.initials: X
authors.lastname: Loyer
authors.forename: Isabell
authors.initials: I
authors.lastname: Flohrschütz
authors.forename: Yassine
authors.initials: Y
authors.lastname: Sassi
authors.forename: Dorothee
authors.initials: D
authors.lastname: Hartmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Thum
authors.forename: Bernhard
authors.initials: B
authors.lastname: Laggerbauer
authors.forename: Stefan
authors.initials: S
authors.lastname: Engelhardt
mesh_terms: D000818:Animals; D049108:Cell Enlargement; D002469:Cell Separation; D002478:Cells, Cultured; D020869:Gene Expression Profiling; D057166:High-Throughput Screening Assays; D035683:MicroRNAs / Q000235:genetics*; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism*; D010641:Phenotype; D061251:Primary Cell Culture; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D014162:Transfection
chemical_list: D035683:MicroRNAs