lecture 7 - Gut organoids Flashcards
(20 cards)
what are the 4 types of stem cell niche adhesion
cadherin
intergrin
cadherin/integrin
non-cadherin/integrin
give some examples of non-cadherin/integrin adhesion
delta/notch
gap junctions
CD44
SCF/C-kit
what is the purpose of stem cell niche adhesion
for the stem cell to stick to its own environment
what is the main adhesion molecule for cadherins
catenin
what are the main adhesion molecules for integrins
talin
actin
what are the other roles for adhesion molecules
directioning/facilitation signalling
asymmetric cell division
competition and quality control
stem cell aging
where is the crypt
in the gut
below the villi, in the spaces inbetween
what are transit amplifying cells
cells between stem and epithelial
sit half way up the crypt cell
which cells types are found in the villi
entrocyte
enteroendocrine
goblet
which signals are expressed at high levels at the base of the crypt
Wnt
Notch
BMP antagonists
EphB
EGF
which signals are expressed at high levels at the top of the villi
Hh
BMP
ephrinB
What do paneth cells secrete and what does this help with
Wnt, Notch and EGF
helps to maintain the stem cell niche
what is Lgr5
marker protein found on real stem cells
works by boosting Wnt signalling
describe the Lgr5 transgenic mice experiment
made a mouse where Lgr5 + cells expressed GFP
then used FACS machine to sort GFP+ and GFP-
after sorting, grew GFP+ cells in culture and found that a single Lgr5+ cell could form a mini gut organoid
what did the Lgr5 transgenic mice experiment prove
Lgr5+ cells are multipotent
in cancer cell lines, Lgr5 and paneth cells move up the crypt
what are organoids
3D structures grown from stem cells which mimic organs
how can gut organoids be formed
from Lgr5+ cells
from PSC/ESCs
describe the developing architecture of gut organoids
budding off
1) Wnt activation
2) induces local proliferation and EphB expression
3) local cells expand and Eph/Ephrin repel eachother
4) bud forms
what are the main uses for gut organoids
detecting mutations
testing patient samples ( eg. for IBS)
regenerative medicine
what does a FACS machine detect
whether you have an antibody bound to a specific protein
