Lecture 11: Stem Cells in Tissues

Question 1

(wasn’t at lecture so may need to look into more)

Somatic SC characteristics

Answer 1

Rare

In human bone marrow

Question 2

Tissues renewed by stem cells

Answer 2

High turnover
Natural
Easily damaged
Common/all?
Include:
Brain
Gut
Skin
Bone marrow

Question 3

Haematopoietic system

Answer 3

bone marrow (hematopoietic stem cell) -> common lymphoid progenitor (->B cell and T cell -> plasma cell and activated T cell), common myeloid progenitor ->granulocyte/macrophage progenitor, megakaryocyte/erythrocyte progenitor (-> neutrophil, eusinophil, basophil, monocyte (granulacytes)->mst cell, osteoclast, macrophage) ->magakaryocyte and erythoblast (->platelets and erythrocyte)
(diagram slide 7)

Question 4

HSC origins

Answer 4

• Generated during embryonic development
• Persist throughout life
• Replace blood cells
• First HSC detected in the AGM region (Aorta, Gonads, Mesonephros)
• Then enter circulation and colonise the liver
• Finally reside in the adult bone marrow

Bone marrow transplantation = HSC transplantation

(slide 8 and 9)

Question 5

Skin Structure

Answer 5

-epidermis (keratinocytes
-dermis (fibroblasts, ECM)
-subcutaneous fat
(more in notes diagram slide 10)

Question 6

Epidermis: layers of keratinocytes

Answer 6

-cornified layer
-granular layer
-spinous layer
basal layer: proliferation, stem cell niche
(11)

Question 7

Keratinocyte differentiation in the epidermis

Answer 7

-BASAL layer of the epidermis is the proliferative compartment.
-BASAL layer contains the Stem Cells which give rise to transient amplifying cells. Transient amplifying cells provide the non proliferative terminal differentiating keratinocytes.
(EGFR activity inhibits Notch, asymmetric division promotes the switch from basal layer cell to spinous cell, high notch activity inhibits integren gene expression???)
-Keratinocytes terminally differentiate as they migrate up through the epidermis
-As keratinocytes differentiate and take on new characteristics they change their molecular profile

Question 8

The hair follicle

Answer 8

-sebaceous gland region
-bulge region
-intermediate region
-bulb region
(look notes slide 14)

Question 9

Clonogenic keratinocytes

Answer 9

-are long-term multipotent stem cells
-Two locations for SC
-Contribution to all hair lineages, sebaceous gland and epidermis (transiently)
-Long life span
(15)

Question 10

How do you get Long-term persistence of hair follicles generated from a single multipotent stem cell?

Answer 10

• one cell->in vitro expansion->grafting->1 cell-> in vitro expansion (karyotype) -> grafting (dermabrasion)
• notes 16 and 17

Question 11

The gut

Answer 11

• Two stem cells described one rarely dividing, one faster
• Give rise to transit amplifying cells
• TA cells differentiate as they move up the crypt
• Movement apparently driven by cell division and active migration
• Cells are shed at tip of villus
• Main cell types: Enterocytes, Goblet cells, Paneth cells, Enteroendocrine cells (18)

Question 12

Mouse neural stem cells (SVZ)

Answer 12

-SVZ astrocytes are adult neural stem cells (B)
-Transit amplifying cells (C) divide rapidly and generate
Neuroblasts (A) which migrate along the Rostral Migratory Stream to the Olfactory Bulb (19)

Question 13

Stem Cell Niche

Answer 13

don’t get this slide (20) look over