08. Stem Cells and Disease

• any change in stem cell quiescence, self renewal or differentiation will lead to disease
• sarcopenia is a loss of muscle mass during ageing

  • due to satellite cell deregulation
  • FGF is normally inhibited by Notch signalling
  • FGF levels increase during ageing and Notch decreases
  • leads to FGF being activated and satellite cells moving out of quiescence
• satellite cells are monopotent stem cells giving rise to skeletal muscle

  • each myofibril is associated with one satellite cell
• limbal stem cell deficiency syndrome = normally regenerate eye surface, but not present leading to cloudy eyes and blindness

  • normally only affects one eye so we can transplant cells from working eye
• quiescence can keep cancer cells alive and cause anti-cancer resistance
• MDR proteins mark quiescent cells, these pump chemicals out of stem cells

  • cancer cells upregulate these
• myelodysplastic syndrome = mutation in HSC population that prevents them going down the right differentiation pathway

  • many types, classified on the type of cell that is dysplastic