Stavridis

Functional definition: stem cell can self-renew and differentiate.

• when differentiated, a stem cell has permenant change of state.

  > how to become permenant: by changing the genetic or epigenetic level of the cell (heritable & beyond cell division; expression maintainance; DNA methylation…etc).

• when self-renew, regeneration by the processes of homeostasis and repair.

  differentiate the cells according to the same lineage.

The ability of single cells to give rise to (all) primary embryonic lineages is termed pluripotency

This explains the aspect of differentiation of a stem cell

Totipotent: zygote

Nullipotent: can only make itself

Gene expression analysis helps in the understanding of the genetic attributes of stem cells.

The intensity of this signature correlates to the level of differentiation across all of the human tissues analyzed.

The intensity of this signature can differentiate the histological grade for a variety of human tumours, this suggests potential therapeutic and diagnostic implications.

The signature is not consistently associated with either the tumor-initiating or non-tumor-initiating population!

There two phases of pluripotency, called naïve and primed.

The formative phase - the relationship between the two phases - is proposed to be a “developmental space” between the naïve and primed phases.

It enables the execution of pluripotency, including remodelling of transcriptional, epigenetic, signalling and metabolic networks to build multi-lineage competence.

(B) cells transit sequentially through naïve to formative to primed forms of pluripotency en route to lineage commitment.