Gastrointestinal Stem Cells and EMT (16,17,18) Flashcards
What is a feature of colon epithelium?
a. There are no villi
b. There is an abundance of +4 stem cells
c. There is an absence of crypt based columnar cells
d. Paneth cells act as niche cells
a. There are no villi
What are the differentiated cell types found in intestinal epithelium?
a. Enterocytes secrete mucus
b. Goblet cells secret hormones
c. Enteroendocine cells are absorptive
d. Paneth cells are immune cells
d. Paneth cells are immune cells
How does Wnt signalling influence intestinal stem cells?
a. APC mutants demonstrate decreased Wnt signalling and a loss of CBC stem cells
b. Increased Wnt signalling can result in adenomatous polyps and colorectal carcinoma
c. An absence of Wnt signalling does not impact the intestinal stem cell pool
d. It down regulates Bmi1 markers to encourage +4 stem cell differentiation
b. Increased Wnt signalling can result in adenomatous polyps and colorectal carcinoma
What causes familial adenomatous polyposis?
a. An inactive Wnt signalling pathway
b. A mutation in APC
c. Under expression of Beta catenin
d. Constitutive production of APC
b. A mutation in APC
How can colorectal cancer be linked to stem cells?
a. Stem cells have no role in the development of colorectal cancer
b. When APC is lost in Transit Amplifying cells, rapidly proliferating adenomas develop
c. Knocking out APC in enterocytes leads to small adenomas that don’t progress
d. When APC is lost in CBC stem cells, rapidly proliferating adenomas develop
d. When APC is lost in CBC stem cells, rapidly proliferating adenomas develop
Which statement is correct?
a. Lgr5+ stem cells and Paneth cells do not interact
b. Paneth cells secrete Wnt and Notch ligands and Lgr5+ stem cells express Fzd7 and Notch 1 recptors
c. Lgr5+ stem cells produce daughter cells symmetrically and by independent choice
d. Lgr5+ cells are niche components that directly influence the activity of Paneth cells
b. Paneth cells secrete Wnt and Notch ligands and Lgr5+ stem cells express Fzd7 and Notch 1 recptors
What is evidence that crypt stem cell populations drift to clonality?
a. Confetti mice exhibited crypts labelled with a single fluoro chrome over a period of months
b. Confetti mice Lgr5 stem cells divided symmetrically and non-stochasitocally and always adopted the fate of a GFP labelled transit amplifying cell
c. Confetti mice exhibited villi labelled with a single fluoro chrome over a period of months
d. Confetti mice exhibited crypts and villi labelled with a single fluoro chrome over a period of months
a. Confetti mice exhibited crypts labelled with a single fluoro chrome over a period of months
How do Wnt and Notch signalling regulate intestinal stem cells?
a. Notch signalling causes Lgr5 and wnt expression in stem cells
b. Cells with high levels of delta activate notch and become absorptive
c. Delta-notch signalling results in lateral inhibition between adjacent cells
d. Wnt leads to the expression of lgr5 and notch in stem cells and down-regulation of Delta in Paneth cells
c. Delta-notch signalling results in lateral inhibition between adjacent cells
How does hedgehog and BMP signalling have a role in regulating the intestinal stem cell niche?
a. BMP4 is expressed in the crypt to repress Hh and Wnt signalling
b. Hh and Wnt signals from the crypt lead to BMP4 expression in the villus core
c. Disrupting hedgehog signalling can lead to ectopic crypts forming in the sides of villi
d. BMP4 expression in the villus core up regulates Hh and Wnt expression in the epithelium
b. Hh and Wnt signals from the crypt lead to BMP4 expression in the villus core
How can organoids self-organise into crypts?
a. Due to BMP4 mediated crypt cell induction
b. Organoids swell when exposed to Forskolin and the addition of exogenous wnt influences crypt formation
c. Paneth cells secret wnt which induces neighbour cells to express EphB which repulse cells expressing EphrinB
d. Paneth cells secrete Delta which can degrade Lgr5+ markers and encourage crypt cell differentiation
c. Paneth cells secret wnt which induces neighbour cells to express EphB which repulse cells expressing EphrinB
• Epithelial cell migration from the crypt to vilus takes 10-15 days.
F
• In the stem cell zone model, it is proposed that transit amplifying cells can de-differentiate back to stem cells.
T
• +4 stem cells are marked with Bmi1 and CBC stem cells are marked with Lgr5.
T
• Lgr5 positive cells can only generate enterocytes and goblet cells.
F
• Lgr5+ stem cells can only build crypt villus structures in vitro if a mesenchymal niche is present.
F