Regulated expression of microRNAs during differentiation of mouse embryonic stem cells into cardiac myocytes

Regulated expression of microRNAs during differentiation of mouse embryonic stem cells into cardiac myocytes

Tomohide Takaya1, Teruhisa Kawamura1, Koh Ono2, Rieko Takanabe1, Shinji Kaichi3, Toru Kita2, Hiromichi Wada1, Tatsuya Morimoto1, Akira Shimatsu1, Koji Hasegawa1.

  1. Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan.
  2. Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
  3. Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan.

第71回日本循環器学会学術集会 (神戸), 2007/03/16 (口演).

Abstract

MicroRNAs (miRNAs) are short non-coding RNAs that repress translation or cleave RNA transcripts. Increasing evidence suggest important roles of microRNAs in various biological processes including cellular differentiation. Previous studies report that microRNA-1 and microRNA-133 are involved in skeletal muscle differentiation, and that microRNA-143 is required for growth inhibition. However, the role of these microRNAs during differentiation of embryonic stem (ES) cells into cardiac myocytes is unknown. Mouse ES cells were cultured with leukemia inhibitory factor (LIF) to maintain undifferentiated state. To induce differentiation, ES cells were cultured for 8 days on 96-well plates without LIF. RNA was isolated from undifferentiated ES cells, differentiation-induced ES cells and the adult mouse heart. Mature microRNA-1, 133b and 143 were specifically amplified by real-time RT-PCR using microRNA-unique primers. All of these three microRNAs were strongly expressed in the adult heart but very weekly expressed in undifferentiated ES cells. Upon induction of differentiation, the amount of each microRNA normalized with that of 5S ribosomal RNA was increased. Among these three microRNAs, cardiac specificity, defined as the expression level in the adult mouse heart relative to that in undifferentiated mouse ES cells, was the highest in microRNA-1 and the lowest in microRNA-143. These findings suggest possible roles of microRNAs in the early stage of myocardial cell differentiation and that microRNA-1 is involved in cardiac specificity.