Figure 4.
AMPK/p27Kip1 Signaling Mediates Cell Survival in the MuSC
Geriatric MuSCs were cultured for 48 hr treated with or without AICAR and/or overexpression of p27Kip1 mutant-p27Kip1(198A).
(A) Percentage of TUNEL-positive cells with respective treatment (N = 4 independent experiments).
(B) Upper: representative blot of total and cleaved PARP; lower: quantification of protein expression normalized to untreated geriatric cells (N = 3 independent experiments).
(C) Percentage of TUNEL-positive cells during Atg5 knockdown with concurrent overexpression of p27Kip1 mutants p27Kip1(198D) or p27Kip1(198A) (N = 3 independent experiments).
(D) Percentage of TUNEL-positive cells during treatment of compound C to young MuSCs with concurrent overexpression of p27Kip1 mutant p27Kip1(198D) (N = 3 independent experiments).
(E) Geriatric MuSCs treated with or without AICAR and infected with respective p27Kip1 mutant lentivirus. Cells were transplanted into injured young SCID muscle and quantified 4 or 28 days later.
(F) Geriatric MuSCs treated with or without AICAR and overexpression of p27Kip1 mutants analyzed 4 days after transplantation.
(G) Quantification of GFP(+) cells per muscle (N = 6 independent experiments).
(H) Geriatric MuSCs treated with or without AICAR and overexpression of p27Kip1 mutants analyzed 28 days after transplantation.
(I) Quantification of GFP(+) myofibers per muscle (N = 6 independent experiments).
Scale bar, 100 μm. ∗ Signifies difference from young or untreated control cells (p < 0.05). Data are presented as means ± SE.