Stem cell biology

Question 1

What are characteristics of a stem cell?

Answer 1

• Has the ability to divide, differentiate into different kinds of cells and selfrenew
• Ability to divide and produce identical daughter cells. This allows them to replenish tissues and organs that are damaged or undergo normal wear and tear
• Power to differentiate into different types of cells, including cells that make up different tissues and organs
• Self renewal, which means they can divide and produce more stem cells. This is important for maintaining a pool of undifferentiated cells that can differentiate into specialized cells when needed

Question 2

What will be produced during Asymmetric stem cell division

Answer 2

• A stem cell
• A more committed cell what can differentiate

Question 3

What will be produced during Symmetric stem cell division

Answer 3

Either 2 identical stem cells or 2 committed cells what can differentiate

Question 4

How can stem cells contribute to the development/progression of cancer?

Answer 4

A source of this process could be ggiven by the fact that cells what are completely differentiated are ‘‘forced’’ to re-enter cell cycle. Stem cells can contribute to this hallmark by becoming cancerous themselves or by providing support to cancer cells in their surrounding environment. In addition, cancer cells also hijack the normal function of healthy stem cells in their environment. This can occur through secration of GF’s and other signaling molecules that stimulate proliferation or survival of stem cells

Question 5

Is it more likely to get cancer from Asymmetrical division, or Symmetric division (of the stem cell)

Answer 5

Loss of Asymmetry can be a cause of cell overproliferation, so symmetric stem cell division

Question 6

Name all the different stem cells

Answer 6

1. Totipotent stem cells: These stem cells have the potential to differentiate into EVERY cell type in the body, INCLUDING the extra-embryonic tissue needed for fetal development
2. Pluripotent stem cell: Same as Toti, but cannot differentiate into the extra-embryonic tissues
3. Multipotent stem cells: These stemcells have the potential to differentiate into a limited range of cells within a particular tissue/organ. Ex: mesenchymal cells
4. Olipoten stem cells (Progenitor stem cells): These are stem cells that have the potential to differentiate into a few closely related cell types. Ex: Myeloid stem cells (several types of blood cells)
5. Unipotent stem cells: These are stem cells that can differentiate into 1 type of cell

Question 7

How do you call cells what cannot differentiate anymore?

Answer 7

Unipotent or nullipotent

Question 8

What is a stem cell niche?

Answer 8

The microenvironment that surrounds a stem cell

Question 9

What 2 mechanisms are there what regulates stem cells and name a few examples

Answer 9

1. Intracellular mechanisms:
   - Asymmetric localization of cytoplasmic determinant
   - Epigenetic regulation
   - Transcriptional regulation (HIPPO)
2. Extracellular mechanisms:
   - Juxtacrine signaling
   - Mechanical force
   - Paracrine signaling
   - Endocrine signaling
   - Neurotransmitter release

Question 10

What are Anoiks in the intestinal crypts

Answer 10

Specific type of Apoptosis due to loss of cell-cell contact. This happens on top of the vili (not crypt)

Question 11

How can ISC (intestinal Stem Cell) keep their ability to divide?

Answer 11

Paneth cells (P) secrete Wnt ligand which stimulate proliferation of the stem cell

Question 12

Which target of ISC is THE stem cell gene and can be tagged with fluorescence?

Answer 12

Lgr5

Question 13

With what transcription factors can a somatic cell (fully differentiated) be reprogrammed into a pluripotent stem cell (induced)

Answer 13

-Klf4
-Sox2 (HIPPO)
-Myc
-Oct4 (HIPPO)