L11.3 Metabolic reprogramming of muscle stem cells

Question 1

Background info for stem cells

Difference b/w quiescent & active SC metabolism

Answer 1

• Glycolysis undergoes the pentose cycle to produce new biomass for proliferating cells (Nucleotides/phospholipids/A.A)
• Embryogenesis activates glycolytic pathways
• Quiescent stem cells: FA metabolism
• Activate stem cells: Glucose metabolism

Question 2

What is reprogramming of muscle stem cells?

Answer 2

• Reprogramming = Reverse differentiated stem cells into pluripotent phase

Question 3

Inducing reprogramming: Galactose

Answer 3

• Produces pyruvate from glycolysis → forces cell to align with oxidative phosphorylation
• Inhibits glycolysis with galactose, ↓myogenic specification

Question 4

Inducing reprogramming: TXNIP

Answer 4

• Pushes cells from cell cycle back into G0 quiescent state
• Different G0 states:
  
  • Quiescent (reversible)
  • Differentiation (irreversible) → becomes myotube/fibres
  • Senescence (irreversible) → lose ability to enter cell cycle

Question 5

Inducing reprogramming PKM1&2

Answer 5

• PKM2 → blocks production of lactate, ↑rate of proliferation
• Each differ only by 1 exon
  
  • PKM1 = has exon 9
    
    • Promotes PEP → pyruvate
  • PKM2 = has exon 10
    
    • Stops PEP → pyruvates → forces cell to stay in glycolysis to produce more biomass