In Vitro Differentiation of Human B.Marrow Mesenchymal Stem Cells to Hair Cells Using Growth Factors

http://www.tinnitusjournal.com/arti...-cells-to-hair-cells-using-growth-factors.pdf

TLDR: researchers in Iran differentiated stem cells from human bone marrow into hair cells using multiple growth factors. Retinoic acid is an essential signal for the regeneration of hair cells, and the gene ATOH1 is important to facilitate cell differentiation into hair cell regeneration.

“It is impossible to transplant adult stem cells and fit them well into the organ of Corti and other approaches are needed”

“Epithelial cell-like colonies have been reported to differentiate more in a retinoic acid (RA) or epithelial growth factor-enriched medium”

“The RA pathway is activated immediately after the loss of hair cells, accelerating the proliferation of cell precursors, and regulating the expression of two key genes, P27kip and SOX2. The results have indicated that RA can be used as an essential signal for the regeneration of hair cells”

“Also, when acoustic trauma occurs accidentally, RA has a protective effect. RA is a clinical drug that is used orally and considered to be healthy. Although the findings can also be used for human, further research is needed to determine the safe and effective dose, duration and time of initiation of drug administration for practical application”

“The first known gene whose expression is associated with hair cell is a basic helix-loop-helix (bHLH) transcription factor called ATOH138. During the development process, the expression of ATOH1 is limited to cells that ultimately differentiate into hair cells. The expression of ATOH1 in the bird's cochlea increases during the process of regeneration of the hair cells... Purposeful loss of ATOH1 leads to complete destruction of the hair cells. In order to regenerate hair cell, transport of a specific gene associated with induction of a hair cell, such as ATOH1, was reported to be effective in mouse. An increase in the expression of ATOH1 in the guinea-pig cochlea after drug-induced hair cell damage led to the retrieval of the 41 hair cell function, in addition to repairing the hair cell. ATOH1 is a major gene to commit to the fate of the hair cells, but we still do not know how the expression of ATOH1 is induced in transplanted cells in vivo, as well as what other genes are needed for the differentiation of the hair cells.”