Stem Cells Flashcards
What is a stem cell?
A cell that can continuously divide in culture to produce unaltered daughter cells with differentiation potential
What are the different types of potency?
totipotent pluripotent multipotent oligopotent unipotent
What potency do adult stem cells have?
multipotent or less
How many types of daughter cells can embryonic stem cells produce?
> 200
How are embryonic stem cells cultured?
self renew
transcription factors repress differentiation
stage identifiable by immunohistocompatability complexes expressed
What are the transcription factors used to repress embryonic stem cell differentiation?
OCT4,
SOX2,
NAN0G,
KLF4
What are the cell surafce markers expressed?
SSEA3, SSEA4, Keratin sulphate Tra-1-60 Tra-1-81
How can pluripotency be tested for?
Clumping of embryoid bodies into 3 germ layers
Transplant into immunosupressed mice produces teratomas
How can cells be induced to pluripotent?
Somatic cells treated with OCT3/4, SOX2, KLF4, c-myc
Where are adult stem cells found?
Quiescent in niches
What are the types of adult stem cell?
haematopoetic
mesenchymal
neuronal
What are haematopoetic stem cells?
Rounded, non adherent cells with low cytoplasmic:nuclear ratio
Have CD34, 45, 117, 14 antigens but haven’t been isolated purely
Found in bone marrow
Produce myeloid tissue
What are mesenchymal stem cells?
Found in bone marrow for bones, connective tissues, cartilage, fat
Limited mortality in vitro
No markers but adhesion molecules
What are neuronal stem cells?
Oligopotent for astrocytes, dendrocytes, neurons
How can stem cells be administered for treatment?
Allogenic
Autologous (self)
How is Multiple Myeloid lymphoma treated?
Autologous
Haematopoetic blood progenitor cells extracted with g-csf
Myleoblastive treatment
Readministeration of stem cells
What are the disadvantages of allogenic transplantation?
limited donor availability stem cell competition attack of donor cells on host cells infection difficult to retain intact niche
What type of diseases can be treated with autologous haematopoetic stem cells?
Aquired: lymphomas and myelomas
What type of diseases can be treated with haematopoetic stem cells?
Aquired or inborn
How are mesenchymal stem cells being developed for treatment?
Regeneration of bones and connective tissue
Tissue engineering
Immunomodulation
How are mesenchymal stem cells administered?
Autologous
Why are embryonic or iPs cells developed?
Wider range of target tissues
Development of drugs to target disease or repair cells
Why are the issues with embryonic stem cells?
Ethical
No immunological
Unknown safety from differentiation
What diseases are modelled with iPs systems?
Parkinsons Type 1 diabetes anaemia Spinal muscular atrophy A1-α-trypsin deficiency β-thallasemia schizophrenia
