In this chapter we focus on the mechanisms and "strategies" by which various niche components support LPCs in liver tissue regeneration, including administration of biomaterials or small molecules that target specific aspects of the niche, to stimulate expansion and differentiation of LPCs, or to cause transdifferentiation of adult liver cells.
However, prolonged acid exposure, acting alone or in concert with other caustic agents, are believed to cause transdifferentiation that involves the replacement of the normal esophageal epithelium with one that resembles the small intestinal epithelium, designated as incomplete intestinal metaplasia since two of four cell types are evident [1].
Ieda and colleagues [ 40] showed that expressing three transcription factors important in heart development, Gata4, Mef2c, and Tbx5, could cause transdifferentiation of fibroblasts into cardiac myocytes.
Another significant problem with existing promoters is that their expression in the luminal epithelium depends on its differentiation; activity is therefore lost if a transgene causes transdifferentiation or dedifferentiation within a tumour.
Wounding of Notch1-deficient cornea causes transdifferentiation into epidermis, a process that involves secretion of fibroblast growth factor-2 (FGF-2) by the epithelium, resulting in vascularisation and remodelling of the underlying stroma [ 30 ]. Notch signalling within melanocytes is required to maintain the melanocyte stem cell compartment [ 22,31 ].
Transdifferentiation between some cell types can occur naturally in response to injury and can be induced experimentally.
Transdifferentiation between liver and pancreas is controlled by only a few transcription factors [ 35, 36].
Via the negative feedback, angiotensin II inhibits the transdifferentiation between the renin-negative SMC and renin-positive SMC.
Subsequent studies have established that cellular-fate conversion is also obtained by direct transdifferentiation between two distinct lineages.
I-type cells may represent either a stem cell or an intermediate stage in the transdifferentiation between N- and S-type cells [3,7].
