Explanation of components in defined iPS medium - (Sep/02/2013 )

Hi everybody,

I would like to ask for you help. I have my iPS cell culture on inactivated mouse embryonic fibroblasts, but we would like to switch to, serum- and feeder-free system from StemCell: "TeSR."

It is well defined, I understand why they use some components like bFGF and so on... But cant reach an answer, why they use these components in medium:

-GABA (γ-Aminobutyric acid)

-Pipecolic acid

-Lithium Chloride (I guess this is used for salt concentration) 

So... any help would be great! I know that this isnt essential knowledge for correct usage of media. I am jut too curious to don't know why they use these components ;)

Johny :)

you may find answer in their patent application https://www.google.com/patents/US8426203

Three of the factors present in TeSR1 (bFGF, TGFβ and LiCl) are believed to stimulate signaling pathways previously highlighted in human ES cell culture publications (see Xu, C. et al. Stem Cells 23, 315-323 (2005); Amit, M. et al. J. Biol. Reprod. 70, 837-845 (2004); and Sato, N. et al., Nat. Med. 10, 55-63 (2004)).

We initially tested GABA because microarray results indicated increased expression of the GABA-A receptor P-3 subunit by human ES cells (see Sperger, J. M. et al. Proc. Natl. Acad. Sci. USA 100, 13350-13355 (2003)). GABA is an inhibitory neurotransmitter of the central nervous system, and is reported to stimulate proliferation of both neural and non-neural tissues (see Watanabe, M., et al. Int. Rev. Cytol. 213, 1-417 (2002)). We tested pipecolic acid as it can enhance GABA-A receptor responses (see Takahama, K. et al. Neuropharmacology 25, 339-342 (1986)).

Thank you sir, for your advice. Its excellent !