Editing Cellular differentiation (section)

{{Short description|Transformation of a stem cell to a more specialized cell}}
{{cs1 config|name-list-style=vanc|display-authors=6}}
{{Redirect|Cell differentiation|the journal|Cell Differentiation (journal)}}
{{Distinguish|Cell division}}
[[File:Final stem cell differentiation (1).svg|thumb|upright=1.5|[[Stem cell]] differentiation into various animal tissue types]]
[[File:Stimuli.pdf|thumb|Cell-count distribution featuring cellular differentiation for three types of cells (progenitor <math>z</math>, osteoblast <math>y</math>, and chondrocyte <math>x</math>) exposed to pro-osteoblast stimulus.<ref name=CME>{{cite journal | vauthors = Kryven I, Röblitz S, Schütte C | title = Solution of the chemical master equation by radial basis functions approximation with interface tracking | journal = BMC Systems Biology | volume = 9 | issue = 1 | pages = 67 | date = October 2015 | pmid = 26449665 | pmc = 4599742 | doi = 10.1186/s12918-015-0210-y | doi-access = free }} {{open access}}</ref>]]

'''Cellular differentiation''' is the process in which a [[stem cell]] changes from one type to a differentiated one.<ref>{{cite book | vauthors = Slack JM | date = 2013 | title = Essential Developmental Biology | publisher = Wiley-Blackwell | location = Oxford | isbn = 9780470923511 }}</ref><ref>{{cite journal | vauthors = Slack JM | title = Metaplasia and transdifferentiation: from pure biology to the clinic | journal = Nature Reviews. Molecular Cell Biology | volume = 8 | issue = 5 | pages = 369–378 | date = May 2007 | pmid = 17377526 | doi = 10.1038/nrm2146 | s2cid = 3353748 }}</ref> Usually, the cell changes to a more specialized type. Differentiation happens multiple times during the development of a [[multicellular organism]] as it changes from a simple [[zygote]] to a complex system of [[Tissue (biology)|tissues]] and cell types. Differentiation continues in adulthood as [[adult stem cell]]s divide and create fully differentiated [[Cell division|daughter cells]] during tissue repair and during normal cell turnover. Some differentiation occurs in response to [[antigen]] exposure. Differentiation dramatically changes a cell's size, shape, [[membrane potential]], [[metabolism|metabolic activity]], and responsiveness to signals. These changes are largely due to highly controlled modifications in [[gene expression]] and are the study of [[epigenetics]]. With a few exceptions, cellular differentiation almost never involves a change in the [[DNA]] sequence itself. Metabolic composition, however, gets dramatically altered<ref>{{cite journal | vauthors = Yanes O, Clark J, Wong DM, Patti GJ, Sánchez-Ruiz A, Benton HP, Trauger SA, Desponts C, Ding S, Siuzdak G | title = Metabolic oxidation regulates embryonic stem cell differentiation | journal = Nature Chemical Biology | volume = 6 | issue = 6 | pages = 411–417 | date = June 2010 | pmid = 20436487 | pmc = 2873061 | doi = 10.1038/nchembio.364 }}</ref> where stem cells are characterized by abundant metabolites with highly unsaturated structures whose levels decrease upon differentiation. Thus, different cells can have very different physical characteristics despite having the same [[genome]].

A specialized type of differentiation, known as [[terminal differentiation]], is of importance in some tissues, including vertebrate [[nervous system]], [[striated muscle]], [[epidermis]] and gut. During terminal differentiation, a precursor cell formerly capable of cell division permanently leaves the cell cycle, dismantles the cell cycle machinery and often expresses a range of genes characteristic of the cell's final function (e.g. [[myosin]] and [[actin]] for a muscle cell). Differentiation may continue to occur after terminal differentiation if the capacity and functions of the cell undergo further changes.

Among dividing cells, there are multiple levels of [[cell potency]], which is the cell's ability to differentiate into other cell types. A greater potency indicates a larger number of cell types that can be derived. A cell that can differentiate into all cell types, including the placental tissue, is known as ''[[totipotent]]''. In mammals, only the zygote and subsequent [[blastomere]]s are totipotent, while in plants, many differentiated cells can become totipotent with simple laboratory techniques. A cell that can differentiate into all cell types of the adult organism is known as ''[[pluripotent]]''. Such cells are called [[Meristem|meristematic cells]] in higher plants and [[embryonic stem cell]]s in animals, though some groups report the presence of adult pluripotent cells. Virally induced expression of four transcription factors [[Oct4]], [[Sox2]], {{Nowrap|[[c-Myc]]}}, and [[Klf4]] ([[Yamanaka factors]]) is sufficient to create pluripotent (iPS) cells from adult [[fibroblast]]s.<ref>{{cite journal | vauthors = Takahashi K, Yamanaka S | title = Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors | journal = Cell | volume = 126 | issue = 4 | pages = 663–676 | date = August 2006 | pmid = 16904174 | doi = 10.1016/j.cell.2006.07.024 | hdl-access = free | s2cid = 1565219 | hdl = 2433/159777 }}</ref> A [[multipotent]] cell is one that can differentiate into multiple different, but closely related cell types.<ref name="Schoeler">{{cite book| vauthors = Schöler HR | veditors = Knoepffler N, Schipanski D, Sorgner SL |title=Humanbiotechnology as Social Challenge|publisher=Ashgate Publishing|year=2007|isbn=978-0-7546-5755-2|page=28|chapter=The Potential of Stem Cells: An Inventory}}</ref> [[Cell potency#Oligopotent|Oligopotent cells]] are more restricted than multipotent, but can still differentiate into a few closely related cell types.<ref name="Schoeler" /> Finally, [[unipotent]] cells can differentiate into only one cell type, but are capable of [[stem cell self-renewal|self-renewal]].<ref name="Schoeler" /> In [[cytopathology]], the level of cellular differentiation is used as a measure of [[cancer]] progression. "[[Grading (tumors)|Grade]]" is a marker of how differentiated a cell in a tumor is.<ref>{{cite web|title=NCI Dictionary of Cancer Terms|url=http://www.cancer.gov/dictionary?CdrID=46445|access-date=1 November 2013|publisher=National Cancer Institute}}</ref>