MGF (Mechano Growth Factor)

What Is MGF (Mechano Growth Factor)?

MGF (Mechano Growth Factor) is the IGF-1Ec splice variant that skeletal muscle produces in response to mechanical loading, eccentric overload, and micro-trauma. After damage, the IGF-1 gene is alternatively spliced to include a unique 24-amino-acid C-terminal E domain, which gives MGF a different role from systemic IGF-1. Rather than broad anabolic signalling, MGF acts locally to move quiescent satellite cells (muscle stem cells between the sarcolemma and basal lamina) out of G0 and into proliferation. Activated satellite cells then fuse with damaged fibres, donating nuclei and enlarging the fibre.

Goldspink's laboratory at University College London (Hill and Goldspink, Journal of Physiology, 2003) first identified this splice event and linked it to satellite cell activation after overload. The 24-residue E-peptide has biological activity independent of the mature IGF-1 portion, driving myoblast proliferation before differentiation is triggered, which is why exogenous MGF behaves differently from IGF-1 LR3 despite the shared IGF backbone. Native MGF has a plasma half-life under 10 minutes. PEG-MGF attaches a polyethylene glycol chain to the molecule, protecting it from proteolysis and extending the half-life to roughly 48 to 72 hours. All efficacy data are from animal and cell models.