MSK L22 Stem Cells Mo shariff Flashcards
ESCs show
Pluripotency → Generate cells derived from all three embryonic cell types: endoderm, mesoderm, ectoderm
ESC’s’ Derived from
Inner cell mas of 4-5 day old blastocyst
Human embryonic germ cells derived from
5-10 week old foetus are also pluripotent
Adult Stem Cells: Definition
Undifferentiated cell found among differentiated cells in a tissue/organ that can renew itself, and differentiate to yield specialised clel types
Adult Stem Cells:Primary role
Is to maintain and repair the tissue in which they are found
Adult Stem Cells: Origin in mature tissues
Unknown but they exist in many tissues
Haematopoietic and mesenchymal cell differentiation:
Step 1: Haemopoeitic stem cell forms a multipotential stem cell
Two lineages:
1. Lymphoid progenitor cells
a. Production of immune cells
2. Myeloid precursor
a. Productino of neutrophils, eosinophils, blood cells etc.
Stromal cells →
- Osteoblasts
- Osteocytes
- Chondroblasts
Adult Stem Cells:
- Adult stem cells typically generate cell types of tissue in which they reside
- Recent experiments indicate stem cells from one tissue can give rise to cells of a completely different tissue = PLASTICITY
a. Haemopoitic stem cells → neurones or muscle
b. Liver cells → made to produce insulin
Trans differentiation →
adult stem cell genetically engineered to behave as embryonic stem cell
ESC characteristics
Pluripotent
Large numbers
Easy to grow in culture
ASC characteristics
o Generally limitied to differentiation into cell types of their tissue origin n.b. evidence of plasticity
o Rare 00> identification and culture methods need
o Own patients cells therefore no rejection
Haemopoitic
- Continuously renewing stem cells
- Continuously formed
- Fluid phase
- Short-lived
- Simple structures (unicellular, matrix-free)
- Inflexible phenotype – little plasticity
Mesenchymal
o Stem cells (not necessarily continuously renewing)
o Formed at certain times
o Solid phase
o Long-lived
o Complex structures (multicell, matrix-bound)
o Plastic phenotype
Multipotent Mesenchymal Stem Cells:
Produced from →
- Bone
- Cartilage
- Adipose tissue
- Fibrous tissue
- Connective tissue