• mouse embryonic stem cells;
  • p38 MAP kinase;
  • differentiation;
  • endothelial cells;
  • smooth muscle cells;
  • neurons


p38 MAP kinase α (p38α) regulates various cellular processes in adult cells, but little is known about its function in stem cells. We investigated the potential of wild type and p38α deficient mouse embryonic stem cells (ESCs) to differentiate into endothelial cells (ECs), smooth muscle cells (SMCs), and neurons. Our differentiation methods allowed simultaneous development of all these cell types. ECs formed monolayers similar to mature ECs and could assemble into vessel-like structures. SMCs had well-organized actin filaments with morphology similar to adult SMCs. Neurons exhibited well-developed cell bodies and elongated axons. Deletion of the p38α gene did not significantly compromise ESC differentiation since p38α−/− cells could express cell-specific markers and displayed similar overall morphology to the cells differentiated from p38α+/+ ESCs. Although p38α regulates various cellular activities of adult SMCs, ECs, and neurons, our data demonstrate that p38α is not essential for ESC differentiation to these cell types. Developmental Dynamics 236:3383–3392, 2007. © 2007 Wiley-Liss, Inc.