The differentiation of amniotic fluid stem cells into sweat glandlike cells is enhanced by the presence of Sonic hedgehog in the conditioned medium.

After patients suffer severe full-thickness burn injuries, the current treatments cannot lead to the complete self-regeneration of the sweat gland structure and function. Therefore, it is important to identify new methods for acquiring sufficient functional sweat gland cells to restore skin function. In this study, we induced CD117+ human amniotic fluid stem (hAFS) cells to differentiate into sweat glandlike (hAFS-SG) cells based on the use of conditioned medium (CM) from the human sweat gland (hSG) cells. Real-time PCR and immunofluorescent staining were used to confirm the expression of the sweat gland-related genes Ectodysplasin-A (EDA), Ectodysplasin-A receptor (EDAR), keratin 8 (K8) and carcino-embryonic antigen (CEA). Transmission electron microscopy analysis shows that microvilli, the cellular structures that are typical for hSG cells, can also be observed on the membrane of the hAFS-SG cells. Our test for the calcium response to acetylcholine (Ach) proved that hAFS-SG cells have the potential to respond to Ach in a manner similar to normal sweat glands. A three-dimensional culture is an effective approach that stimulates the hAFS-SG cells to form tubular structures and drives hAFS-SG cells to mature into higher stage. We also found that epidermal growth factor enhances the efficiency of differentiation and that Sonic hedgehog is an important factor of the CM that influences sweat gland differentiation. Our study provides the basis for further investigations into novel methods of inducing stem cells to differentiate into sweat glandlike cells.