Let me be clear: if we want to sustain stem cell research and bring new cures and treatments to millions of people, I believe admixed embryos are necessary.
However, graphene and its derivatives [graphene oxide (GO), and reduced graphene oxide (rGO)] have all shown to induce and sustain stem cell growth and differentiation with considerable efficacy, while being capable of enhancing osteogenic differentiation [22].
Interestingly, it has been shown with mouse embryonic cells that Id proteins, such as Id3, in conjunction with STAT3 sustain stem cell self-renewal and inhibit differentiation[56].
Depending on the concentration of ATP in the extracellular milieu, it can act by sustaining stem cell proliferation (Aa in Tab. 3 of mathematical model), by leaving stem and progenitor cells in a resting state (Ai in Tab. 3) or by killing SVZ cells and neurons (excitotoxicity).
Indeed, EZH2 can directly methylate the promoters of transcription factors that are essential for sustaining stem cell pluripotency [ 8].
Thus, a critical amount of Oct3/4 is required to sustain stem cell self-renewal, and up- or downregulation induces divergent developmental programs.
Second, the transcription factor, Oct4, is able to encode two functional isoforms, Oct4A and Oct4B, whereas only the Oct4A isoform is able to sustain stem cell properties [ 26].
Id1 sustains stem cell phenotype as it controls the expression of Sox2, responsible for stem cell self-renewal, and promotes cadherin switching, which has been associated to epithelial mesenchymal transition.
These experiments demonstrate the overarching importance of the signals provided by mammary epithelial cells for the development of a microenvironment(s) capable of sustaining stem cell activity and differentiation.
