About this Research Topic
Pluripotent stem cells can generate cells of lineages from all three germ layers, ectoderm, mesoderm, and endoderm. In the very early embryos, all cells are pluripotent. Embryonic Stem cells (ES cells), isolated from the inner cell mass of the blastocyst, are the prototype of pluripotent stem cells. Multipotent and unipotent stem cells generate cell types found in the tissue of origin or, at most, in lineages derived from the same germ layer. In mammals, after birth, pluripotent cells are maintained in the bone marrow and possibly in the gonads. The existence of pluripotent stem cells in adult tissues and in peripheral blood still is a debated issue among scientists, whereas multipotent stem cells were isolated from a variety of adult tissues.
Gametes are also pluripotent cells since they can give rise to a new individual of the same species. Oocytes are formed at a relatively early stage of development, whereas spermatozoa are continuously produced during their whole life. Therefore, the question is: are there pluripotent stem cells in gonads, especially in men, from which gametes are derived?
The isolated pluripotent cells are characterized by the expression of cell surface stage-specific embryonic antigens (SSEA) and pluripotent genes, also expressed in the early embryos such as Oct3/4, Sox2, Klf4, Nanog, and c-Myc. s. Moreover, they have lost the teratogenic and tumorigenic properties. These cells were variously described and named in the literature. A decline in the differentiation efficiency of both in vitro and in vivo cells derived from older donors in both mice and humans has been reported. Epigenetic modifications are probably responsible for this. Adult pluripotent stem cells are quiescent and self-renew at a very low rate. They are maintained in that state under the influence of the “niche” inside which they are located. Any tissue damage causes the release in the blood of inflammatory cytokines and molecules that activate the stem cells and their mobilization, homing, and redifferentiation in the injured tissue. Our interest in adult tissue-resident stem cells extends to their adoption in clinics for the treatment of several degenerative pathologies.
As an alternative, the inflammatory response also determines the dedifferentiation of mature cells and their reversion to a progenitor stage. Dedifferentiation is a transient process by which cells become less specialized and return to an earlier cell state within the same lineage. After birth, in mammals, including humans, except for the liver, dedifferentiation, and redifferentiation have been observed mostly in in vitro cell cultures. However, at most, dedifferentiated cells can be considered tissue-specific multipotent stem cells. They maintain the memory of the tissue of origin and are not able to generate tissues derived from other germ layers.
We welcome original research articles, reviews, methodological papers, perspectives, and data reports that contribute to an increased understanding of adult pluripotency and advancement in the field.
Gametes are also pluripotent cells since they can give rise to a new individual of the same species. Oocytes are formed at a relatively early stage of development, whereas spermatozoa are continuously produced during their whole life. Therefore, the question is: are there pluripotent stem cells in gonads, especially in men, from which gametes are derived?
The isolated pluripotent cells are characterized by the expression of cell surface stage-specific embryonic antigens (SSEA) and pluripotent genes, also expressed in the early embryos such as Oct3/4, Sox2, Klf4, Nanog, and c-Myc. s. Moreover, they have lost the teratogenic and tumorigenic properties. These cells were variously described and named in the literature. A decline in the differentiation efficiency of both in vitro and in vivo cells derived from older donors in both mice and humans has been reported. Epigenetic modifications are probably responsible for this. Adult pluripotent stem cells are quiescent and self-renew at a very low rate. They are maintained in that state under the influence of the “niche” inside which they are located. Any tissue damage causes the release in the blood of inflammatory cytokines and molecules that activate the stem cells and their mobilization, homing, and redifferentiation in the injured tissue. Our interest in adult tissue-resident stem cells extends to their adoption in clinics for the treatment of several degenerative pathologies.
As an alternative, the inflammatory response also determines the dedifferentiation of mature cells and their reversion to a progenitor stage. Dedifferentiation is a transient process by which cells become less specialized and return to an earlier cell state within the same lineage. After birth, in mammals, including humans, except for the liver, dedifferentiation, and redifferentiation have been observed mostly in in vitro cell cultures. However, at most, dedifferentiated cells can be considered tissue-specific multipotent stem cells. They maintain the memory of the tissue of origin and are not able to generate tissues derived from other germ layers.
We welcome original research articles, reviews, methodological papers, perspectives, and data reports that contribute to an increased understanding of adult pluripotency and advancement in the field.
Keywords: Muse cells, Very Small Embryonic Like cells, VSELs, Mesenchymal Stem Cells, Stem cell niche, Cell dedifferentiation, Pluripotent genes, SSEA3/4.
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.
