Transcription factor KLF2 regulates cell fate decision of stem cells in infantile hemangioma

As the most common vascular tumor during infancy, infantile hemangioma (IH) is clinically featured by a rapid proliferation phase of disorganized blood vessels and a subsequent spontaneous involution phase. Infantile hemangioma arises from a unique type of multipotent stem cells called hemangioma stem cells (HemSCs), which could differentiate into endothelial cells, pericytes and adipocytes in IH. However, the underlying mechanisms that regulate the cell fate determination of HemSCs are not well elucidated. Here, we identified KLF2 as a candidate transcription factor involved in the control of HemSCs differentiation. KLF2 was expressed in endothelial cells in proliferating IH and its expression diminished in adipocytes in involuting IH. KLF2 regualtes the proliferation, apopotosis and cell cycle progression in HemSCs. Moreover, KLF2 is a critical regulator in HemSCs that control their differentiation direction between endothelial cells and adipocytes. Knockdown of KLF2 inhibited the formation of blood vessels in vivo while accelerated the progress of adipogenesis. RNA-seq analysis suggested an induction of pro-adipogenic transcriptome in HemSCs upon KLF2 knockdown. Our data showed that KLF2 exhibited pleiotropic effects in regulating the biological behaviours of HemSCs, and was involved in the progression and involution of IH via determining the cell fate of HemSCs.