Abstract: The present invention relates to the use of human-derived microRNAs (miRNAs) as targets for the identification of cardiac and cardiac-like cell types. In particular, it relates to a specific set of miRNAs which have been found to be correlated to cardiac differentiation and can act to up or downregulate a number of putative mRNA targets to guide differentiation and also act as markers for a cardiac phenotype. In addition, it also relates to the use of these miRNAs as tools for the isolation, selection, purification and characterisation of cardiac and cardiac-like cells and tissues. The invention also encompasses the possible use of these miRNAs in the differentiation and maturation of cardiac or cardiac-like cell types.

Abstract: A cluster is provided comprising cardiomyocyte-like cells, wherein the cluster has i) contracting cells, ii) cells that are electrically connected, and expresses iii) cardiac markers including Nkx.2.5, troponin and myosin, iv) markers for functional adrenergic receptors, v) markers for functional muscarinic receptors, vi) markers for functional ion-channels including hERG, Na+, Ca2+ and K+ channels, vii) one or more endodermal markers selected from the group consisting of AFP, TF, APOA2, AHSG, SERPINA1, APOA1, APOC3, TTR1 APOB, and RBP4. A method for preparing the clusters and methods utilizing the clusters in drug discovery and toxicity screenings are described.