NKX2-5 and atrial fibrillation: The relative expression of the main cardiac gene markers NKX2-5 (encoding an early cardiac transcription factor Nkx2.5), MYH6 (α-myosin heavy chain), TNNT2 (cardiac troponin T), and DES (Desmin) was upregulated in AF-MSCs differentiated with all agents or their combinations at days 5 and 12 of differentiation compared to undifferentiated control (Figure 2B).