ISL1 and fibrosis: To check whether the alterations in these repressive epigenetic marks were associated with altered expression of target genes involved in cardiac fibrosis and hypertrophy, we measured the expression level of isl lim homeobox 1 (ISL1) (Figure 3A), six homeobox 1 (SIX1) (Figure 3B) and mads box transcription enhancer factor 2, polypeptide C (MEF2C) (Figure 3C).