Ch. 5 pt 2 Flashcards
Intestinal stem cells differentiate as they move upwards away from the _______
crypt
Intestinal cells undergo _______ at the tips of the villi
anoikis
What are the 2 paracrine gradients for the intestinal epithelium stem cell niche?
1) Wnt2b
2) Bmp4
_______ promotes proliferation by binding to the Frizzled 7 receptor
Wnt2b
_______ promotes differentiation of ISC’s by binding to the bmpr1 receptor
Bmp4
Where are hematopoietic cells located?
bone marrow
- 1.15 million cells a second
Hematopoietic stem cell niche was first described by Russian _______
Alexander Maximov (stammzelle)
HSC’s aren’t created in the bone marrow but find their way into the marrow during development through a process called “______”
homing
Describe homing of Hematopoietic stem cells (4 terms)
-
CXCL4 receptor binds to CXCL12
chemokine produced by osteoblasts and
stromal cells of the marrow - E-selectins and VCAM are also involved
What are the 2 regions of the hematopoietic stem cell niche?
1) endosteal niche
2) perivascular niche
In the endosteal niche, division is focused on _______ organism survival of stem cell population and HSC’s interact directly with _______
long-term
osteoblasts
In the perivascular niche, division is _______ for renewing progenitor populations for short periods of time and HSC’s are associated with _______
short-term
blood vessels
_______ cells can give rise to multiple cell lineages and play an important role in tissue repair/regeneration
multipotent cells
What are 2 examples of multipotent stem cells?
part 2
bone-marrow derived stem cells (BMDC)
mesenchymal stem cells (MSC)
Mesenchymal stem cells are found in many adult tissues and resemble fibroblasts, but can be cultured to _______ and produce a variety of _______
self-renew
cells
Mesenchymal cell differentiation can be driven by _______ and _______
paracrine factors
interactions with ECM
The identification of _______ in many organs presents exciting hopes for new types of therapies to repair/regenerate diseased or damaged parts
adult stem cells
- in very small numbers with slow proliferation
______ show that even in small numbers adult stem cells can be used to reproduce an entire functional organ/organ system
bone marrow transplants
- ex) single transplanted cell in mice to reproduce blood, immune system, mammary gland
The _______ is probably the most widely studied cell type in the world and was taken from _______
HeLa cell line
human tumors
- henrietta lacks
- Died in 1951 (cancer)
_______ pluripotent stem cells from ICM of early blastocysts
embryonic stem cells (ESC)
_______ from primordial germ cells that have not yet differentiated into sperm or egg
Embryonic germ cells (EGC)
______ ESC: most undifferentiated, greatest potential for pluripotency
naive
_______ ESC: some maturation towards epiblast lineage, possible reduction in pluripotency.
primed
Pluripotency of ESC is maintained in culture by core TF’s: (3)
1) Oct4
2) Nanog
3) SOX2
What inhibitors are used to maintain ESC state? (2)
1) Leukemia inhibitory factors (LIF)
2) kinase inhibitors (2i)
- MEKi
- GSK3i
in 2006 researchers in japan demonstrated that by inserting activated copies of 4 genes they could transform nearly any adult cell into an _______
Induced pluripotent stem cells (iPSC)
What are the 4 Yamanaka factors?
1,2) Oct4/Sox2 - activates nanog and other TF
3) C-Myc - opens up chromatin
4) Klf4 - prevents cell death
______ homeodomain transcription factor that helps establish ESC identity
Nanog
Know there are medical uses for iPSC’s
Sickle cell anemia transplant in mouse
Researchers have been able to grow rudimentary organs from pluripotent stem cells called _______, which are generally small and can be maintained in culture for extended periods of time
organoids
- will self organize due to cell adhesion
cerebral organoids were made by placing brain tissue organoids into matrixgel and then moving neuroepithelial buds into a _______
spinning bioreactor
-increased nutrient uptake and growth
Stem cell research may be the beginning of a revolution that will be as important for medicine (and as transformative for society) as the research on infectious _______ was a century ago
microbes
Stem cells certainly give credence to the view that, “_______ never stops”
development
