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Intestinal crypt

Intestinal sub-epithelial myofibroblasts are SMA, desmin cells that secretes HGF, KGF, TGFβ and regulates epithelial cell's differentiation. Interstitial cells of Cajal are SMA, desmin, c-Kit and CD45 cells in proximity of neurons, to transmit electrical potential that regulates movement of the gastrointestinal tract.

Previously, mesenchymal cells (which are normally the niche cells) are thought to be required to maintain primary intestinal epithelial culture. However, in these cell cultures, Lgr5 ISCs are not observed.

Note that Lgr are also found in multipotent stem cells of the pylorus, and that Lgr cells and Sox2 cells do not overlap, at least not at the levels observable by immunohistochemistry. Using Ki67 as a proliferation marker, it was shown that about half of the Sox2 cells proliferate in homeostatic conditions,showing heterogeneity within the adult stem cell population.

Hair follicle

The cells near the dermis expresses markers such as keratin 5/14. Different markers are also expressed - keratin 1/10, involucrin, cornifin, and transglutaminase-1 are xpressed in the spinous layer of the epidermis; loricrin, filaggrin, and keratohyalin are expressed in granular layers of the epidermis.

The heterogeneity can be attributed to the location in the body. Follicle morphogenesis comes in waves, guard follicles are generated around E14.5 and have long straight shafts, awl and auchene follicles are generated around E16.5 and have long, straight or singly-kinked shafts, shafts on the back of mice are generated around E18.5 and is shaped like a zigzag (with two kinks).

Only a low level of β-catenin is required for hair follicle fomation from sebaceous glands and interfollicular epidermis, whereas a high level of β-catenin is required for new follicles to form from preexisting follicles; this can be a mechanism in which hair follicle formation is controlled which has a large leeway.

The mouse dermis taken from sites of hair formation can induce follicles in any epithelium when transplanted, whereas dermis taken from sites of non-hair formation cannot induce follicles.

fibroblasts from the head and face derive from the neural crest, dorsal and ventral trunk fibroblasts are derived from the dermomyotome of somitic and lateral plate, respectively.

Mice are born nude, and hair begin to grow only after about 10 days. The first two cycles are synchronized, after which they become desynchronized. Thus, it is advisable to study young mice, as they are all synchronized and expresses the same factors.

1. Evans, GS; Flint, N; Somers, AS; Eyden, B; Potten, CS (1992). "The development of a method for the preparation of rat intestinal epithelial cell primary cultures". Journal of cell science. 101 ( Pt 1): 219–31. PMID 1569126.
2. Barker, N; Huch, M; Kujala, P; Van De Wetering, M; Snippert, HJ; Van Es, JH; Sato, T; Stange, DE; Begthel, H (2010). "Lgr5(+ve) stem cells drive self-renewal in the stomach and build long-lived gastric units in vitro". Cell stem cell. 6 (1): 25–36. doi:10.1016/j.stem.2009.11.013. PMID 20085740.
3. Cite error: The named reference Doistem was invoked but never defined (see the help page).
4. Silva-Vargas, Violeta; Lo Celso, Cristina; Giangreco, Adam; Ofstad, Tyler; Prowse, David M.; Braun, Kristin M.; Watt, Fiona M. (2005). "Β-Catenin and Hedgehog Signal Strength Can Specify Number and Location of Hair Follicles in Adult Epidermis without Recruitment of Bulge Stem Cells". Developmental Cell. 9 (1): 121–31. doi:10.1016/j.devcel.2005.04.013. PMID 15992546.