LincRNA encoded in the MyoD upstream maintains epigenetic myogenic memory in myoblast-derived iPSCs

LincRNA encoded in the MyoD upstream maintains epigenetic myogenic memory in myoblast-derived iPSCs

Jesse L Mull1, Takehiro Nagatsuka1, Tomohide Takaya1, Shuichi Watanabe1, Yoko Asakura1, Michael A Rudnicki2, Charles P Emerson Jr3, Atsushi Asakura1.

  1. Stem Cell institute, Paul & Sheila Wellstone Muscular Dystrophy Center, Department of Neurology, University of Minnesota Medical School, Minneapolis, MN, USA.
  2. Molecular Medicine, Ottawa Health Research Institute, Ottawa, ON, Canada.
  3. Wellstone Muscular Dystrophy Program, Departments of Cell & Developmental Biology and Neurology, University of Massachusetts Medical School, Worcester, MA, USA.

The 6th Annual Cardiovascular Retreat (Minneapolis, USA), 2014/07/30 (Poster).

Abstract

Induced pluripotent stem cells (iPSCs), which have been generated from a variety of somatic cells through the use of reprogramming factors, hold tremendous therapeutic promise due to their ability to differentiate into virtually any cell type. Recent studies suggest that iPSCs retain a propensity to differentiate into their tissue of origin due to epigenetic memory. In light of these developments, we have recently established myoblast-derived iPSCs (MB-iPSCs) (Watanabe et al., Stem Cells, 2011). Importantly, MB-iPSCs show a bias towards myogenic differentiation compared to fibroblast-derived iPSCs (FB-iPSCs). In addition, MB-iPSCs, but not FB-iPSCs, display low expression levels of myogenic genes, including MyoD, indicating that myogenic genes are not fully silenced in MB-iPSCs. However, DNA methylation patterns of the MyoD promoter (PRR) and two enhancers (DRR and CE) are not significantly different between MB-iPSCs and FB-iPSCs. Interestingly, our cDNA screening has identified several polyadenylated alternative splicing variants of recently identified CERNA, an enhancer-derived long intergenic noncoding RNA (linc RNA) transcribed from the CE within the MyoD regulatory region (Mousavi et al., Mol Cell, 2013). One of the variants termed CERNA-1 is up-regulated in MB-iPSCs compared to FB-iPSCs. Overexpression of CERNA-1 in primary myoblasts and embryonic stem (ES) cells enhanced MyoD transcription and myogenic differentiation. Therefore, the up-regulation of CERNA-1 in MB-iPSCs is responsible for epigenetic myogenic memory. Thus, MB-iPSCs offer a valuable means of investigating the molecular mechanisms in the reprogramming process due to the well-defined nature of muscle development. In addition, MB-derived iPSCs can differentiate into myogenic cells more readily than FB-derived iPSCs due to the up-regulation of CERNA-1, potentially forming the basis for a novel cell therapy for muscle diseases. Supported by NIH 5R01AR062142-02.