Isolation of Pluripotent Neural Crest-Derived Stem Cells from Adult Human Tissues by Connexin-43 Enrichment

Identification and isolation of pluripotent stem cells in adult tissues represent an important advancement in the fields of stem cell biology and regenerative medicine. For several years, research has been performed on the identification of biomarkers that can isolate stem cells residing in neural crest (NC)-derived adult tissues. The NC is considered a good model in stem cell biology as cells from it migrate extensively and contribute to the formation of diverse tissues in the body during organogenesis. Migration of these cells is modulated, in part, by gap junction communication among the cell sheets. Here we present a study in which, selection of connexin 43 (Cx43) expressing cells from human adult periodontal ligament yields a novel pluripotent stem cell population. Cx43(+) periodontal ligament stem cells express pluripotency-associated transcription factors OCT4, Nanog, and Sox2, as well as NC-specific markers Sox10, p75, and Nestin. When injected in vivo into an immunodeficient mouse model, these cells were capable of generating teratomas with tissues from the three embryological germ layers: endoderm, mesoderm, and ectoderm. Furthermore, the cells formed mature structures of tissues normally arising from the NC during embryogenesis such as eccrine sweat glands of the human skin, muscle, neuronal tissues, cartilage, and bone. Immunohistochemical analysis confirmed the human origin of the neoplastic cells as well as the ectodermal and endodermal nature of some of the structures found in the tumors. These results suggest that Cx43 may be used as a biomarker to select and isolate the remnant NC pluripotent stem cells from adult human tissues arising from this embryological structure. The isolation of these cells through routine medical procedures such as wisdom teeth extraction further enhances their applicability to the regenerative medicine field.