Lecture 1: Stemcells - Types & functions

Question 1

What are some potential uses of stem cells?

Answer 1

Stroke, ad, Pd, hd, Tbi

Question 2

What is the hierarchy of stem cells?

Answer 2

Totipotent (fertilised egg) → pluripotent (blastocyst) → multipotent (hematopoetic, neural, meserchymal) → lineage committed

Question 3

What 2 functions do stem cells possess?

Answer 3

• Self renewal → copying → maintain pool
• differentiation → specialising → replace dead and damaged cells throughout life

Question 4

Where are stem cells?

Answer 4

Embryonic → in the blastocyst - inner cell mass
Tissue → in the foetus, baby, & adult

Surface of eye, skin, testes, muscles, brain, breast, gut, bone marrow

Question 5

What are the principles of renewing tissues?

Answer 5

• Stem cells → self renew, divide rarely, high potency, rare
• committed progenitors → transient amplifying cells, multipotent, divide rapidly, limited self-renewal
• specialised cells → work, no division

Question 6

What is the path of the haematopoietic stem cell?

Answer 6

Bone marrow (hsc) → committed progenitors →
• nk cells, T cells, B cells
• dendritic cell
• megakaryocyte → platelets
• erythrocyte
• macrophage
• neutrophil

Question 7

What is the path of the mesenchymal stem cell?

Answer 7

Bone marrow (MSc) → committed progenitors →
• osteoblasts
• cartilage
• adipocytes

Question 8

What is the path of neural stem cells?

Answer 8

Brain (NSC) → committed progenitors →
• neurons, interneerons
• oligodendrocytes
• Astrocytes

Question 9

What is the path of gut stem cells?

Answer 9

Small intestine (Gsc) → committed progenitors →
• paneth cells
• goblet cells, endocrine cells
• columnar cells

Question 10

Explain induced pluripotent stem cells

Answer 10

• Patient → iPSC → differentiated cells → disease in a dish → screening → drugs → patient

iPSC production
• source cell acquisition → source cell expansion → iPSC generation (introduction of reprogramming factors) → iPSC characterisation (gene expression, epigenetics, pluripotency)

Question 11

Which methods can be used to make new stem cells?

Answer 11

• integrating Viral vectors → retroviral, lentiviral
• integration free → viral vectors, plasmid DNA, recombinant proteins, synthetic mRNA

One of the above is introduced to somatic cells with certain Tfs → iPSC → iPSC line

Question 12

How are ipsc produced?

Answer 12

Step 1: establishment of cell culture
Step 2: generation of ipsc
Step 3: characterisation & expiation of ipsc

Question 13

Reprogramming using episomal plasmids

Answer 13

1. Induction
2. Reprogramming
3. Reprogrammed
4. Differentiation into embryonic germ layers
5. Normal karyotype

Question 14

What keep ipsc pluripotent in culture?

Answer 14

secreted factors
• cell feeder layer (no longer required) → good cos we know exact contents now of media
• leukemia inhibitory factor
• bone morphogenetic proteins
• fgf-2 & Tgf

Question 15

Differentiation of a stem cell

Answer 15

Stem cell + extrinsic signals + growth factors → progenitor cell

progenitor cell + extrinsic signals → fissure specific differentiated cell

Question 16

Differentiation of pluripotent stem cells

Answer 16

Pluripotent → multipotent → differentiated

Es/ipsc → ecto/meso/endo - dermal → tissue