tissue stem cells & regeneration

Question 1

what is a stem cell

Answer 1

ability to differentiation into diverse range specialised cell types
ability to renew itself indefinitely
some become quiescent
proliferat în niches formed by differentiated somatic cells

embryonic stem cells (pluripotent)
adult stem cells (tissue stem cells) (multipotent, unipotent) e.g. haematopoetic SC

Question 2

progenitor cells & transient-amplifying cells

Answer 2

limited number of cell divisions before differentiation
usually limited self renewal, but replenished from stem cells
differentiate into one or few related cell types

Question 3

current limitations for stem cell therapy

Answer 3

immune rejection of SCs from donors, other than identical twin or patients themselves

inadvertent tumour formation from transplanted stem cells

insufficient no. SCs for effective therapy

Question 4

commonly used markers for adult stem cells

Answer 4

yes-associated protein (YAP)
transcriptional co-factor in hippo signalling, controls organ sizee and progenitor cell proliferation

ABCG2
membrane transporter protein
expels toxic metabolites out of cells (SCs need to protect themselves from mutation)

Question 5

evidence for adult stem cells

Answer 5

markers
side populations of small cells with big nucleus
lack of differentiation markers
label retaining - slow proliferation
ability of single cell to contribute to multiple tissue types
regeneration after injury/disease