Figure 4. Glycogen Storage Contributes to PHD2^KD Cell Survival by Supplying Energy.

(A) Glycolytic flux of cultured control (ctr) and PHD2^KD mPDC (n=9).

(B) Glucose oxidation rate (N.S. is not significant, n=9).

(C) Palmitate β-oxidation (n=6).

(D) Cell viability during normal (5 mM glucose) or glucose-deprived conditions (0.5 mM glucose) (n=9).

(E-F) Intracellular glycogen deposition, quantified after periodic acid-Schiff (PAS) staining (E) or determined after extraction (F) (n=9).

(G-H) Cellular glycogen content after inhibition of PYGL with DAB (G) or shRNA (PYGL^KD; H) (n=6).

(I-J) Cell viability of control, PHD2^KD and PHD2^KD cells after inhibition of PYGL. PYGL was inhibited in PHD2^KD cells using DAB (I) or shRNA (PHD2^KDPYGL^KD; J) (n=4-6).

(K) Energy status (ratio of ATP to AMP levels) (n=3).

(L) P-AMPK^T172, AMPK and β-actin immunoblot, with quantification of p-AMPK^T172 to AMPK ratio (n=3).

(M-N) Intracellular ROS levels in control, PHD2^KD and PHD2^KD cells after inhibition of PYGL. PYGL was inhibited in PHD2^KD cells using DAB (M) or shRNA (PHD2^KDPYGL^KD; N) (n=4-6).

(O) TUNEL immunostaining with quantification of TUNEL⁺ cells in the scaffold center at day 3 after implantation (scale bar, 100 μm; n=4).

Data are means ± SEM. **p<0.01 vs. ctr, ***p<0.001 vs. ctr (Student’s t-test), #p<0.05, °p<0.05 vs. ctr in normal culture conditions, ^§p<0.05 vs. ctr during glucose deprivation (ANOVA).