A new type of heart stem cell is described online in Nature this week. Identifying such progenitor cells could eventually be useful for cardiac regeneration and repair.
Scientists already know that the heart is formed from cardiogenic progenitors expressing the transcription factors Nkx2-5 and Isl1. These progenitors are multipotent ? they can give rise to heart and smooth muscle and to endothelial cells. William Pu and colleagues show that a new type of cardiac progenitor, marked by the transcription factor Wt1, resides in certain heart and pre-heart tissue. During normal heart development a subset of these precursors differentiate into fully functional heart muscle, and they arise from Wt1 progenitors that express both Nkx2-5 and Isl1. This suggests that they share a developmental origin with other multipotent progenitors and could help researchers to identify a new pool of heart stem cells.