L8 - adult stem cell niches

Question 1

What is a stem cell niche?

Answer 1

A local tissue microenvironment that hosts and influences the behaviours and characteristics of stem cells

Question 2

What was Schofield’s SC niche hypothesis?

Answer 2

A stem cell niche:

• has a defined anatomical location
• regulates self renewal
• removal from niche results in stem cell differentiation

Question 3

What do successful bone marrow TP require and what does this imply?

Answer 3

Irradiation of existing HSCs within the endogenous BM. This suggests that tp and endog HSCs are competing for a limited source of supporting niches

Question 4

What are the 3 key components of a SC niche?

Answer 4

cell: cell interaction
cell: ECM interaction
cell: soluble signal interaction

Question 5

Explain cell:cell interaction

Answer 5

Stromal and support cells interact through

• cell surface receptors
• gap junctions
• soluble factors

Question 6

Explain cell:ECM interactions

Answer 6

ECM/cell adhesion molecules;

• provide anchor for SC to niche
• polarity cue for orientation of SC mitotic spindle

Question 7

Explain cell:soluble interactions

Answer 7

Autocrine and paracrine factors
Can act locally or throughout the niche
Secrete factors for maintaining SC identity