![]() ![]() Other well-documented examples of transdifferentiation and their significance in development and regeneration were described in detail. They form characteristic cell clusters in suspension culture that express a set of genes associated with pluripotency and can differentiate into endodermal, ectodermal and mesodermal cells both in vitro and in vivo. For instance, multilineage-differentiating stress-enduring (Muse) cells are stress-tolerant adult human stem cells that can self-renew. Ī variety of nontumorigenic stem cells display the ability to generate multiple cell types. This capacity to regenerate does not decline with age and may be linked to their ability to make new stem cells from muscle cells on demand. In newts, muscle tissue is regenerated from specialized muscle cells that dedifferentiate and forget the type of cell they had been. Īfter injury, mature terminally differentiated kidney cells dedifferentiate into more primordial versions of themselves and then differentiate into the cell types needing replacement in the damaged tissue Macrophages can self-renew by local proliferation of mature differentiated cells. Differentiated airway epithelial cells can revert into stable and functional stem cells in vivo. Moreover, they can make this transition even in the absence of noticeable injuries and are capable of replenishing entire gastric units, in essence serving as quiescent "reserve" stem cells. While they normally produce digestive fluids for the stomach, they can revert into stem cells to make temporary repairs to stomach injuries, such as a cut or damage from infection. For example, "chief" cells express the stem cell marker Troy. Some types of mature, specialized adult cells can naturally revert to stem cells. They showed that opposing gradients of bone morphogenetic protein (BMP) and Nodal, two transforming growth factor family members that act as morphogens, are sufficient to induce molecular and cellular mechanisms required to organize, in vivo or in vitro, uncommitted cells of the zebrafish blastula animal pole into a well-developed embryo. The researchers were able to identify the minimal conditions and factors that would be sufficient for starting the cascade of molecular and cellular processes to instruct pluripotent cells to organize the embryo. The fact that transdetermination (change of the path of differentiation) often occurs for a group of cells rather than single cells shows that it is induced rather than part of maturation. In Drosophila imaginal discs, cells have to choose from a limited number of standard discrete differentiation states. This process allows the body to replace cells not suitable to new conditions with more suitable new cells. One example is the transformation of iris cells to lens cells in the process of maturation and transformation of retinal pigment epithelium cells into the neural retina during regeneration in adult newt eyes. This transition can be a part of the normal maturation process, or caused by an inducement. The reversible transformation of cells of one differentiated cell type to another is called metaplasia. In 1924 Hans Spemann and Hilde Mangold demonstrated the key importance of cell–cell inductions during animal development. This meant that the cells can change their differentiation pathway. In 1895 Thomas Morgan removed one of a frog's two blastomeres and found that amphibians are able to form whole embryos from the remaining part. Transformation of somatic cells into stem cells, using the genetic material encoding reprogramming protein factors, recombinant proteins microRNA, a synthetic, self-replicating polycistronic RNA and low-molecular weight biologically active substances.Fusion of somatic cells with pluripotent stem cells and.Transplantation of nuclei taken from somatic cells into an oocyte (egg cell) lacking its own nucleus (removed in lab).Progenitors are obtained by so-called direct reprogramming or directed differentiation and are also called induced somatic stem cells. They are classified as either totipotent (iTC), pluripotent (iPSC) or progenitor (multipotent – iMSC, also called an induced multipotent progenitor cell – iMPC) or unipotent – (iUSC) according to their developmental potential and degree of dedifferentiation. Induced stem cells ( iSC) are stem cells derived from somatic, reproductive, pluripotent or other cell types by deliberate epigenetic reprogramming. ![]()
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