Stem cells Flashcards
What are the three division modes of stem cells?
- Asymmetric self-renewing = a progenitor and a new stem cell
- symmetric differentiating = two progenitors made
- Symmetric self-renewing= produce more stem cells
What totipotent?
single cells zygote and 4 to 8 cell embryo generates the embryo and extra embryonic tissue
What is pluripotent?
inner cell mass (ICM)/ embryonic stem cells generate the embryo proper
What is multipoint?
Tissue specific, Adult or somatic cells, generate adult tissue
What influences stem cells functions and behaviour ?
stem cell niche- their microenvironment
What regulates stem cells?
- signalling = paracrine, NT and endocrine signalling
- Tissue mechanics = ECM to reg actin and cell shape
- epigenetics and post transcriptional regulation
Where are embryonic stem cells derived from ?
the ICM (inner cell mass)
What are the characteristics of ES cells?
pluripotent and undifferentiated
What do ICM clones do?
give rise to endoderm, mesoderm and ectoderm
What is the key initiation step in the establishment of ICM?
Asymmetric cell division
How are ICM cells created?
Asymetrical divison perpendicular to apicoblast axis
Unequal distribution of fate determinants = ICM cells created
What do Oct4, Sox2 and Nanog do to maintain ICM cells ?
Drive pluripotent gene expression network of the ICM
Differentially repressed during development to give the epiblast
How is the trophectoderm fate maintained ?
Apical polarity-mediated inhibition of hippo signalling
What are induced pluripotent stem cells do?
- form cell types representative from all 3 germ layers
- generate entire embryo
- pluripotent
what are some of the medical uses for iPS cells ?
Patient specific = able to model disease
Combined with gene therapy
No immune rejection
Screen drugs and toxicity testing
